http://apologeticspress.org/APContent.aspx?category=11&article=4778
What is “Sexual Immorality” in Matthew 19:9?
                    
                    
 
From
 Genesis to Revelation, the Bible repeatedly stresses the fact that God 
designed the institution of marriage (Genesis 2:22-25). He has, from the
 beginning of human history, given very specific ideas about what 
composes a divinely approved marriage (Matthew 19:1-4), consisting of 
one man and one woman. We learn from the Scriptures, however, that not 
every man or woman is qualified to enter into certain marital 
relationships. In the New Testament, we read of three, and only three, 
categories of people whom God approves to enter into marriage. The first
 category is those who have never been married (Hebrews 13:4). The 
second category of people who are eligible to marry is those who have 
been married but whose spouses have died (Romans 7:1-3). The third 
category of God-approved marriage candidates is those whose spouses have
 committed “sexual immorality” (Matthew 19:9). It is to this last 
category and to the term “sexual immorality” that we will direct our 
attention.
 In Matthew 19:1-10, Jesus was tested by the Pharisees with the 
following question: “Is it lawful for a man to divorce his wife for any 
reason?” Jesus responded by directing their attention to God’s original 
creation of Adam and Eve. They then queried why Moses allowed 
certificates of divorce if marriage was supposed to be such a permanent 
institution. Jesus responded:
 
  Moses, because of the hardness of your hearts, permitted you to 
divorce your wives, but from the beginning it was not so. And I say to 
you, whoever divorces his wife, except for sexual immorality, and 
marries another, commits adultery; and whoever marries her who is 
divorced commits adultery (Matthew 19:8-9).
Notice, from this verse, that any person who gets a divorce for any 
reason other than sexual immorality, and marries another, commits 
adultery. But a person who divorces his/her spouse for sexual immorality
 and marries another person does not commit adultery. Thus, Jesus gives 
the criterion for those who are in the third category of God-approved 
marriage candidates. Also notice those who are not eligible to enter 
into a marriage: anyone who has gotten a divorce for any reason other 
than sexual immorality. [NOTE: The parallel passage found in Matthew 
5:32 quotes Jesus as saying: “But I say to you that whoever divorces his
 wife for any reason except sexual immorality causes her to commit 
adultery; and whoever marries a woman who is divorced commits 
adultery.”]
 With Jesus’ statement in mind, it becomes imperative to learn what the 
term “sexual immorality” means, since this is the only infraction on 
behalf of a spouse that would allow for the remarriage of the innocent 
party (the spouse who does not commit sexual immorality) after a 
divorce. As you can imagine, in our culture of rampant divorce and 
remarriage, and secularized Christianity, this word has been given all 
sorts of meanings in an attempt to allow virtually every divorced person
 to be considered a God-approved candidate for remarriage. Many of these
 definitions are nothing more than attempts to alter the Word of God. So
 then, what does “sexual immorality” mean?
 In order to understand what Jesus was saying, we must go back to the 
original language and identify what the word meant in the first century.
 The word translated “sexual immorality” in this verse is the Greek word
 
porneia. The respected Greek lexicon of Arndt, Gingrich, and 
Danker states that the word refers to “prostitution, unchastity, 
fornication, of every kind of unlawful sexual intercourse.” In their 
primary definition, they mention that it refers to “the sexual 
unfaithfulness of a married woman” (1979, p. 693). 
The NIV Theological Dictionary of New Testament Words has an extensive section on 
porneia
 and related words: “This word group describes various extramarital 
sexual modes of behavior insofar as they deviate from accepted social 
and religious norms (e.g., homosexuality, promiscuity, pedophilia, and 
esp. prostitution)” (Verbrugge, 2000, 6:1077). This dictionary further 
notes: “Rab. Jud. (Rabbinical Judaism—KB) frowned on any kind of 
prostitution of extramarital sexual intercourse. Incest and all kinds of
 unnatural sexual intercourse were viewed as 
porneia (6:1078). In the discussion of the word’s use in the New Testament, the volume states:
 
  It is not clear whether porneia in the so-called ‘exceptive 
clause’ (Matt 5:32; 19:9) is to be understood simply as extramarital 
sexual intercourse in the sense of moicheia or as including prostitution. Most interpreters tend to favor the former interpretation…. The porne word group denotes any kind of illegitimate sexual intercourse in Paul’s letters (6:1078, emp. added).
The
Theological Dictionary of New Testament Words says 
concerning this word group that the “NT is characterized by an 
unconditional repudiation of all extra-marital and unnatural 
intercourse” (Hauck and Schultz, 1968, 6:590). In discussing the word as
 it is used in Matthew 5:32 and Matthew 19:9, this source states: “In 
both verses 
porneia refers to extra-marital intercourse on the 
part of the wife, which in practice is adultery” (6:592). From a survey 
of the lexical information regarding the word, the almost universally 
understood meaning of the word 
porneia is illicit physical 
sexual intercourse with someone who is not the person’s God-approved 
spouse (this would include homosexuality and beastiality). In modern 
terminology, then, the text is simply saying that the only time a person
 can divorce his or her spouse and marry another is if that spouse has 
been involved in a sexual affair with someone else. With knowledge of 
this word’s actual meaning, let us examine how some have attempted to 
redefine the term. [NOTE: Mark 10:11-12 is evidence of the fact that the
 Scripture applies both to a man who divorces his wife and to a woman 
who divorces her husband. The divine regulations apply equally to both 
genders. See Lenski, 1998, p. 734.]
 Any Type of Lewd or Licentious Behavior
In our modern culture the term “pornography” has a host of meanings. It
 includes pictures of scantily clad men and women, videos of people 
engaged in illicit sexual situations, posters of women or men “baring it
 all,” etc. The word “pornography”derives from the word 
porneia. One can see the obvious connection. Due to the fact that “pornography”seems so similar to 
porneia, many have come to believe that any actions or behavior that modern people would term 
pornography would also fall under the definition of 
porneia. Thus, they suggest that if a person were to look at a pornographic movie, he would be guilty of 
porneia. If
 a wife were to send a man who is not her husband text messages with 
photos of herself in her underwear, or with messages that talk about 
sexual situations, she would be guilty of 
porneia. If a spouse were to call a phone-sex line and listen to a sexual situation described to him, he would be guilty of 
porneia. And the list could go on and on.
 The problem with this line of reasoning is that it projects a definition of the word 
porneia
 onto the first-century Greek term that the word in the first century 
did not have. Notice that in the definition provided from the lexical 
resources, there is near universal consensus that the term meant “sexual
 intercourse.” Due to the way the term “sex” has been overly applied to 
modern activities such as “phone sex,” or “sexting,” and “sexy,” the 
modern understanding is that anything that would be “sexually arousing” 
would be included in the term “sex.” But the term 
porneia would not have been understood to have such a loose, broad meaning.
 It should be noted, of course, that many of the activities that have 
been described such as “sexting” or phone sex would be sinful and would 
be included in numerous lists of thoughts and actions that Christians 
should avoid. The terms for such activities include licentiousness, 
lusts (1 Peter 4:3), or lewdness (Romans 13:13). These terms have a much
 broader definition than 
porneia. Since that is the case, if 
Jesus had wanted to use one of these terms with a broader definition 
than “sexual intercourse” He could have, but He chose not to. As Wayne 
Jackson correctly stated: “Bible translations that render 
porneia
 more generically (e.g., ‘sexual immorality’) are misleading. There are 
various forms of sexual immorality (e.g., exposing one’s body in 
seductive clothing) that do not fall under the definition of 
fornication, though clearly they are sinful” (n.d.).
 We get a definite understanding of how first-century Jews understood 
the term in John 8. In that passage Jesus accused the Jews of being the 
children of the devil, because they were behaving in the same way the 
devil would behave. They responded to His accusation by saying, “We were
 not born of fornication, we have one Father—God” (John 8:41). The word 
translated “fornication” in this verse is 
porneias. Notice their understanding of the term 
porneias included the idea that a person could be born of 
porneias.
 That would imply that the term must mean more than looking at 
pornographic pictures or explicit conversations about sex. In this 
context, it would be narrowly defined as sexual intercourse that has the
 biological ability to produce offspring. [NOTE: While the Jews had 
“spiritualized” the term and applied it to their spiritual relationship 
with God, that does not change the meaning of the word as they 
understood it. They certainly meant that they were not “illegitimate” 
spiritual children born as the result of an extra-marital sexual 
encounter. The fact that the term was figuratively applied to a 
spiritual relationship does not alter its literal meaning. See the 
section of this article titled “Sexual Immorality Used to Describe 
Idolatry.”]
 The response to this statement from those who desire to view 
porneia as
 having a broader meaning is that “sexual intercourse” is such a 
difficult concept to define. Obviously, they say, homosexual behavior 
cannot produce offspring. Bestiality cannot produce offspring. So, 
according to them, any attempt to put limits on the nature of such 
“sexual” activity is doomed to failure. Such reasoning has at least two 
glaring flaws. First, it misses the point that the word 
porneia
 had a first-century meaning that was understood in the context as 
extra-marital sexual intercourse. Second, such reasoning fails to take 
into account the fact that in order to accept a broader definition for 
the term 
porneia, positive evidence must be presented that 
shows the word was understood in the first century to have the looser 
meaning. It is not enough to say, “I really feel like the term would 
include looking at pornography, sexting, or phone sex.” 
Any 
person who believes such activities would be included in the definition 
must present lexical information and first-century usages of the word 
that show such activities could be a part of the word’s meaning.
 Without this type of positive proof, we must stick with the definition 
that can be shown from the Bible and lexical sources to have been in use
 in the first-century.
 Practically speaking, then, suppose a wife were to confide in a 
preacher that her husband is viewing pornography and masturbating. She 
asks the preacher if these transgressions would allow her to 
scripturally divorce her husband and be a candidate to remarry. The 
preacher then explains that 
porneia is the only divinely sanctioned cause for divorce and subsequent remarriage. The woman wants to know if 
porneia
 would include what she has described. The preacher shows her the 
lexical information and biblical usage and explains that “sexual 
intercourse” is the key component of the word. The woman argues that 
masturbation could be included in the term “sexual intercourse.” The 
preacher then goes to John 8:41, explains how the word was used there, 
and asks the woman to do some study and try to find any instance in or 
around the time of the first century where we know for a fact the word 
was used for masturbation or viewing pornography. If such a usage is not
 forthcoming, the only proper course of interpretation is to exclude 
masturbation and viewing pornography from the definition of 
porneia. 
 What About Matthew 5:27-28?
Once it has been clearly established that 
porneia is the only 
exception given for a spouse to scripturally divorce and contract a 
subsequent marriage, some then turn to Matthew 5:27-28 to broaden the 
meaning of 
porneia. Those verses record Jesus saying: “You have
 heard that it was said to those of old, ‘You shall not commit 
adultery.’ But I say to you that whoever looks at a woman to lust for 
her has already committed adultery with her in his heart.” The reasoning
 is, if a man lusts for a woman other than his spouse, Jesus says he has
 committed adultery with her “in his heart.” Since he commits 
mental/heart adultery, the argument goes, that must mean his wife could 
divorce him for “adultery” based on his lustful thoughts, and she could 
contract another scriptural marriage. This argument is flawed on several
 levels.
 First, notice where Jesus said the “adultery” takes place: “in his 
heart.” In Matthew 5:27-28, however, Jesus makes a distinction between 
what He is saying in Matthew 5:32 and Matthew 19:9. In neither of the 
latter two instances does Jesus allow for the adultery to be in any 
other realm but physical. The word 
porneia carries no inherent 
meaning that would cause the reader to interpret it to mean anything 
other than physical sexual intercourse. Since “in his heart” or other 
such phrases are not included in Matthew 5:32 or 19:9, correct 
interpretation rules would require us to define the word 
porneia
 in physical terms, not mental or spiritual ones. As Wayne Jackson 
correctly stated: “A fundamental principle of Bible interpretation is 
that words must be interpreted literally unless there is compelling 
reason for assigning them a figurative meaning. The term ‘adultery’ is 
not employed in a metaphorical sense in Matthew 19:9” (n.d.).
 Second, we must recognize that while certain sins may carry the same 
spiritual weight, they do not have the same physical consequences. In 
Matthew 5:21, Jesus explained that the Old Testament prohibited murder. 
He elaborated on this concept when He insisted that any person who hates
 his brother enough to say, “You fool,” will “be in danger of hell fire”
 (Matthew 5:22). The inspired writer John said: “Whoever hates his 
brother is a murderer, and you know that no murderer has eternal life 
abiding in him” (1 John 3:15). From these passages it is clear that the 
sins of hatred and murder carry the same spiritual weight, but they do 
not carry the same physical consequences. In the Old Testament, murder 
was a capital offense punishable by death, but hatred was not. Again, 
physical adultery was a crime punishable in the Old Testament by 
stoning, but lust was not. In Matthew 19:9, the sin of 
porneia 
may carry the same spiritual weight as lust “in the heart,” but the 
verses never hint at the idea that the terms carry the same physical 
consequences. The physical consequences of a spouse committing 
porneia are
 that the innocent spouse can divorce that person and contract a new 
scriptural marriage, while the guilty party must remain unmarried for 
the rest of his or her life. The same physical consequences are not 
enumerated for “adultery in the heart” in Matthew 5:28.
 Sexual Immorality Used to Describe Idolatry
In a similar way, some have contended that because God used the terms 
“adultery,” or “sexual immorality,” or equivalent ideas to describe the 
Israelites’ apostasy into idolatry (Hosea 4:11-13), then the terms can 
have a broader meaning. They argue that if God’s people can commit 
“adultery” against Him by worshipping idols, then the word “adultery” 
must have a meaning broad enough to include activities other than 
actual, physical intercourse.
 Again, this type of argument fails for at least two primary reasons. First, it is clear from the 
context of
 Matthew 19:1-9 that the physical relationship between a husband and 
wife is under discussion. Respected linguists Vine (1985) and Thayer 
(1962, p. 532) concur that  when not used metaphorically (in reference 
to idolatry) 
porneia is used of “illicit sexual intercourse.” 
There is no discussion in this context of idolatry or spiritualized 
unfaithfulness. The text could not be clearer in regard to the physical 
marriage relationship.
 Second, the spiritualized, figurative sense of the word makes no sense 
if the Jews did not understand the physical sense as the primary, 
literal meaning. For instance, in Hosea 4:12, in regard to Israelite 
idolatry, the prophet said: “Therefore your daughters commit harlotry 
and your brides commit adultery.” In a physical sense, what do the terms
 “adultery” and “harlotry” mean?—illicit sexual intercourse. Without the
 understanding of the 
physical meanings, the 
illustration that God used makes no sense—that in a figurative sense, 
Israel is married to God, and idolatry is a spiritual act of 
unfaithfulness. Unless adultery really does mean committing sexual sin 
against one’s spouse, God’s illustration breaks down.
 For instance, consider the statement: “The debater blew his opponent’s 
argument out of the water.” This figurative use of the phrase only makes
 sense if we understand the physical picture of literal water and some 
type of blasting explosion. The figurative use of the word is always 
dependent on the physical meaning of the term. The physical meanings of 
the terms are necessarily logically prior to the figurative or 
spiritualized meanings. Thus, spiritual “adultery” can only be 
understood if we comprehend the physical use of the term “adultery.” And
 we have sufficiently established that the physical use of 
porneia means illicit sexual intercourse.
 Finally, and worthy of serious consideration, is this fact: even if it could be shown that 
porneia might have a spiritualized, figurative meaning in Matthew 19:1-9 (which it cannot), that fact would only indicate a 
possible
 use of the word. The one contending that a person could contract a God 
approved divorce and subsequent remarriage would have to 
prove that this spiritualized usage is being applied,
 not just that it is a possibility.If
 that usage cannot be proven beyond the shadow of a doubt, then a person
 would be risking his or her soul on a mere possibility. What kind of 
ground would a person be standing on in the Day of Judgment contending 
with God, “But I thought the word possibly could have meant…,” when we 
have a very clear meaning of “physical sexual intercourse” that we know 
the word carries.
 Conclusion
Marriage is permanent. The only two situations in the New Testament in 
which a person can get married more than once with God’s approval are 
when a spouse dies, or when an innocent spouse divorces a spouse for 
porneia. The term 
porneia means
 unlawful, physical sexual intercourse. In an attempt to broaden the 
category of those who can scripturally remarry, some have attempted to 
define the term 
porneia with concepts such as viewing pornography or “phone sex.” While those activities are sinful, they are not 
porneia
 as the word was used in the first century. Others have contended that 
lust results in “adultery in the heart” and would be grounds for a 
scriptural divorce and remarriage. But they fail to differentiate 
between sins that have the same spiritual weight but have different 
physical consequences. Jesus’ sole exception for divorcing a living 
spouse and marrying another is if that spouse has committed physical 
sexual intercourse with another biological being.
 REFERENCES
Arndt, William, F.W. Gingrich, and Frederick W. Danker (1979), 
A Greek-English Lexicon of the New Testament and Other Early Christian Literature (Chicago, IL: University of Chicago Press), second revised edition.
 Hauck, F. and Siegfried Schultz (1968), 
porneia, 
Theological Dictionary of the New Testament, ed. Gerhard Kittel (Grand Rapids, MI: Eerdmans).
 Jackson, Wayne (No Date), “Is ‘Lust’ the Equivalent of ‘Fornication’”, 
Christian Courier, http://www.christiancourier.com/articles/1371-is-lust-the-equivalent-of-fornication.
 Lenski, R.C.H. (1998), 
The Interpretation of St. Matthew’s Gospel (Minneapolis, MN: Augsburg).
 Thayer, Joseph (1962), 
Greek-English Lexicon of the New Testament (Grand Rapids: Zondervan).
 Verbrugge, Verlyn (2000), 
The NIV Theological Dictionary of New Testament Words(Grand Rapids: Zondervan).
 Vine, W.E. (1985), 
Vine’s Expository Dictionary of Biblical Words (Nashville: Thomas Nelson, Electronic PC Study Bible Version).