What (if Anything) is Sexually Immoral?

In the final two chapters of the Bible we read a description of the exotic New Heaven, New Earth, and it's capital, New Jerusalem. These will all be just small tokens of God's affection for His people. In the middle of the 837 word description (NIV), there's an interesting comment about people who won't be invited:

Revelation 22:15 Outside are the dogs, the sorcerers, the sexually immoral, the murderers, the idolaters, and everyone who loves and practices falsehood.

It's not an aberration, it's a recurring theme:

Revelation 21:8 But for the cowardly, unbelieving, sinners, abominable, murderers, sexually immoral, sorcerers, idolaters, and all liars, their part is in the lake that burns with fire and sulfur, which is the second death.”

Revelation 9:21 They didn’t repent of their murders, their sorceries, their sexual immorality, or their thefts

If we are to end up citizens (rather than visitors or outcasts) of the wonderful place described at the very end of the Bible, then like any citizen of any locality, we must honor the ruler. One way we do that is by avoiding the things that are forbidden by law. Our culture struggles with all of these, and when our culture struggles, we have to be intentional to rise above the crowd. Remember the book of Revelation is a vision from Jesus to the apostle John, as recorded in the very first verse:

Revelation 1:1 This is the Revelation of Jesus Christ, which God gave Him to show to His servants the things which must happen soon, which He sent and made known by His angel to His servant, John

So let's be intentional about that final description in Revelation 22:15, and make sure we understand God's expectations:

• dogs
• unbelievers, cowardly believers, perverters of the faith
• Numbers 32:15, Deuteronomy 11:16-17, DT 23:18 ESV, Matthew 7:6, Luke 12:46, Philippians 3:2
• sorcerers
• witchcraft, magic arts, divination, necromancy, etc.
• Exodus 22:18, Leviticus 19:26, 19:31, 20:6, 20:27, Deuteronomy 18:10-11, 18:14
• sexually immoral
• (see below)
• murderers
• ending the life of another human being for our own convenience (self defense and military defense do not fit this definition)
• Exodus 20:13, 22:2, Deuteronomy 5:17
• idolaters
• believing in, worshipping, or giving divine credit to, any god (or anything) besides the one true God
• Exodus 20:3-6, Deuteronomy 5:7-10, 6:14-15, Isaiah 42:8
• loves and practices falsehood
• calling evil good and good evil, a.k.a. lying and encouraging others to do the same
• Exodus 20:15-17, Psalm 119:163, Proverbs 17:15, Isaiah 5:20, Romans 1:32

Since it seems to keep us out of heaven, and is reason to be thrown into hell, sexual immorality is an important topic. And doubly so when we take in context our current culture says sexual freedom is a basic human right to be defended even stronger than life and liberty. So what -is- sexual immorality? We know what sexual activity is but do we know how God has defined sexual immorality?

While mentioned 3 times in Revelation, above, sexual immorality isn't defined in these passages. So how are we to avoid it to avoid being left outside? Remember, when we are stuck before a judge, we don't interpret the law for the judge, the judge interprets for us. Let's work backward and review when sexual immorality is referred to, to find how God defined it. Because He wouldn't have absolutely condemned it without explaining Himself.

Revelation 2:20 I have this against you, that you tolerate your woman, Jezebel, who calls herself a prophetess. She teaches and seduces my servants to commit sexual immorality, and to eat things sacrificed to idols.

Revelation 2:14 I have a few things against you, because you have there some who hold the teaching of Balaam, who taught Balak to throw a stumbling block before the children of Israel, to eat things sacrificed to idols, and to commit sexual immorality.

Jude 1:7 Even as Sodom and Gomorrah and the cities around them, having in the same way as these given themselves over to sexual immorality and gone after strange flesh, are shown as an example, suffering the punishment of eternal fire.

Hebrews 13:4 Let marriage be held in honor among all, and let the bed be undefiled; but God will judge the sexually immoral and adulterers.

Hebrews 12:16a lest there be any sexually immoral person, or profane

1 Thessalonians 4:3 For this is the will of God: your sanctification, that you abstain from sexual immorality,

1 Timothy 1:9-11 that law is not made for a righteous person, but for the lawless and insubordinate, for the ungodly and sinners, for the unholy and profane, for murderers of fathers and murderers of mothers, for manslayers, for the sexually immoral, for homosexuals, for slave-traders, for liars, for perjurers, and for any other thing contrary to the sound doctrine, according to the Good News of the glory of the blessed God, which was committed to my trust.

Colossians 3:5 Put to death therefore your members which are on the earth: sexual immorality, uncleanness, depraved passion, evil desire, and covetousness, which is idolatry.

Ephesians 5:3-5 Sexual immorality, and all uncleanness or covetousness, let it not even be mentioned among you, as becomes saints; nor filthiness, nor foolish talking, nor jesting, which are not appropriate, but rather giving of thanks. Know this for sure, that no sexually immoral person, nor unclean person, nor covetous man, who is an idolater, has any inheritance in the Kingdom of Christ and God.

Galatians 5:19-21 The deeds of the flesh are obvious, which are: adultery, sexual immorality, uncleanness, lustfulness, idolatry, sorcery, hatred, strife, jealousies, outbursts of anger, rivalries, divisions, heresies, envy, murders, drunkenness, orgies, and things like these; of which I forewarn you, even as I also forewarned you, that those who practice such things will not inherit God’s Kingdom.

2 Corinthians 12:21 when I come my God would humble me before you, and I would mourn for many of those who have sinned before now, and not repented of the uncleanness, sexual immorality, and lustfulness which they committed.

1 Corinthians 10:8 Let’s not commit sexual immorality, as some of them committed, and in one day twenty-three thousand fell. (Referring to Numbers 25:8-9.)

1 Corinthians 6:18 Flee sexual immorality! “Every sin that a man does is outside the body,” but he who commits sexual immorality sins against his own body.

1 Corinthians 6:13 “Foods for the belly, and the belly for foods,” but God will bring to nothing both it and them. But the body is not for sexual immorality, but for the Lord; and the Lord for the body.

1 Corinthians 6:9-10 don’t you know that the unrighteous will not inherit God’s Kingdom? Don’t be deceived. Neither the sexually immoral, nor idolaters, nor adulterers, nor male prostitutes, nor homosexuals, nor thieves, nor covetous, nor drunkards, nor slanderers, nor extortionists, will inherit God’s Kingdom.

1 Corinthians 5:1 It is actually reported that there is sexual immorality among you, and such sexual immorality as is not even named among the Gentiles, that one has his father’s wife.

Romans 13:13 Let’s walk properly, as in the day; not in reveling and drunkenness, not in sexual promiscuity and lustful acts, and not in strife and jealousy.

Romans 1:28-32 Even as they refused to have God in their knowledge, God gave them up to a reprobate mind, to do those things which are not fitting; being filled with all unrighteousness, sexual immorality, wickedness, covetousness, malice; full of envy, murder, strife, deceit, evil habits, secret slanderers, backbiters, hateful to God, insolent, arrogant, boastful, inventors of evil things, disobedient to parents, without understanding, covenant breakers, without natural affection, unforgiving, unmerciful; who, knowing the ordinance of God, that those who practice such things are worthy of death, not only do the same, but also approve of those who practice them.

Acts 15:29 that you abstain from things sacrificed to idols, from blood, from things strangled, and from sexual immorality, from which if you keep yourselves, it will be well with you. Farewell.” (also in Acts 15:20 and Acts 21:25)

Mark 7:21-23 For from within, out of the hearts of men, proceed evil thoughts, adulteries, sexual sins, murders, thefts, covetings, wickedness, deceit, lustful desires, an evil eye, blasphemy, pride, and foolishness. All these evil things come from within, and defile the man.”

Matthew 15:19 For out of the heart come evil thoughts, murders, adulteries, sexual sins, thefts, false testimony, and blasphemies.

So in the whole new Testament, despite it being mentioned over two dozen times, we saw very little definition of sexual immorality. We saw in some cases critical mention of adultery, homosexuality, incest, lust, and prostitution, along with it, but it wasn't quite defined. And it's not clear in these contexts if those examples were separate from or specific examples of, which the authors chose to single out. The answer for the quest for the definition must be further back towards the beginning of the book. Which is fine, this just means the definition didn't change when Jesus walked among us for a few decades.

By the way, if you don't care what the Bible says, that would be one thing. But if you claim the Bible is vague on, or even affirming of, sexual immorality, then that's naive at best, deceptive and wicked at worst.

There was no new theology between Joshua and Malachi. (Joshua was the first book after the Pentateuch, and Malachi was the last book before the Gospels.) The last book of the Pentateuch (the five books written by Moses) was Moses's greatest sermon, titled Deuteronomy, which means "repetition of the law." It was a repetition because it had already been explained in Exodus and Leviticus. The corrupt leaders of Jesus's day tried to criticize Him for violating those laws Moses had given. But they were corruptly mixing in their own traditions with God's laws, wrongly equating their own word with God's, and Jesus called them out on that. Notice Jesus never said the law no longer mattered, He said He fulfilled it better than they understood (Matthew 5:17). Before we get into the law, I want to point out a related administrative theme the quasi-apostle Paul brought up:

Romans 7:7 (NIV) What shall we say, then? Is the law sinful? Certainly not! Nevertheless, I would not have known what sin was had it not been for the law. For I would not have known what coveting really was if the law had not said, “You shall not covet.”

Romans 3:20 (NIV) No one will be declared righteous in God’s sight by the works of the law; rather, through the law we become conscious of our sin.

Romans 5:20-6:2 (NIV) The law was brought in so that the trespass might increase. But where sin increased, grace increased all the more, so that, just as sin reigned in death, so also grace might reign through righteousness to bring eternal life through Jesus Christ our Lord. What shall we say, then? Shall we go on sinning so that grace may increase? By no means! We are those who have died to sin; how can we live in it any longer?

The law isn't salvific, Jesus is. Yes Jesus died for our sins, and He washes them all away, but He was pretty clear He predicated that favor on our repentance. And what are we to repent from but the immorality defined in the moral law of Moses?

Matthew 4:17 From that time, Jesus began to preach, and to say, “Repent! For the Kingdom of Heaven is at hand.”

Matthew 9:13 But you go and learn what this means: ‘I desire mercy, and not sacrifice,’ for I came not to call the righteous, but sinners to repentance.”

Matthew 11:20 Then he (Jesus) began to denounce the cities in which most of his mighty works had been done, because they didn’t repent.

Revelation 3:19 As many as I love, I reprove and chasten. Be zealous therefore, and repent. (And don't forget Revelation 9:20-21​ above)

Since there's no definition from Joshua to Revelation, we must look back further, in the law. And sure enough, there were numerous definitions. So many definitions we'd think God was trying to make a point and be clear about it, as if He only wanted to have to say it once for all time. Here are the verses in the law that defined sexual immorality, divided into obvious categories just for digestibility:

• Adultery: Exodus 20:14, Deuteronomy 5:18
• Bestiality: Exodus 22:19, Leviticus 18:23, Leviticus 20:15-16, Deuteronomy 27:21
• Crossdressing: Deuteronomy 22:5
• Homosexuality: Leviticus 18:22, Leviticus 20:13
• Incest: Leviticus 18:6-18, 20:11-12, 20:14, 20:17, 20:19-21, Deuteronomy 22:30, 27:20, 27:22-23
• Prostitution: Leviticus 19:29, 21:9, Deuteronomy 23:17-18
• Sex before marriage: Exodus 22:16-17, Deuteronomy 22:21, 28-29
• Sex during menstration: Leviticus 18:19, 20:18
• Other: Deuteronomy 23:1, 25:11-12

And here's that same list again, sorted by occurrence.

• Exodus 20:14, 22:16-17, 22:19
• Leviticus 18:6-19, 18:22-23, 19:29, 20:11-21, 21:9
• Deuteronomy 5:18, 22:5, 22:21, 22:30, 23:1, 23:17-18, 24:1-4, 25:11-12, 27:20-23

What God calls immoral is immoral (also wrong and evil), regardless of whether it's legal or protected. It doesn't matter how long ago He said it nor who He said it to. And whether people genuinely love each other was never described as relevant to sexual propriety. That consideration was maliciously fed to us by people who wanted to alienate (separate) us from God, no matter how normal that perversion has become in society. The word of God stands on its own (it's sufficient). Either you care what the Bible says or you don't, I'm just connecting the dots so we can know what it says on these topics, and hoping you are clear the Bible is clear on these topics. I assure you I haven't excluded any verses that contradict or negate the ones I included. This blog post is dedicated to the direct verses. There are yet more (less direct) verses and perhaps more importantly, an exploration into why God even cares about what we do in bed, then check my more exhaustive article: Biblical Gender Identity, here, summarized in a blog post, here, or my blog post on morality in general, here.

(Note: all scripture quotes were from the World English Bible (WEB) except where indicated otherwise.)