Many modern translations of the Bible have falsely interpreted the Greek word porneia (πορνεια) as "immorality," "sexual immorality," or "marital unfaithfulness." Even several lexicons, dictionaries, preachers, teachers, and theologians have attempted to claim that all sorts of sexual perversion—incest, homosexuality, bestiality, prostitution, harlotry, etc.—is included in this Greek word—as well as adultery. However, this is false. This word is correctly interpreted as "fornication." An examination of every passage where this word is used will show that if you let the Bible interpret itself—in context, in none of these passages does this word mean anything more than illicit sexual acts committed by unmarried persons (single, betrothed [engaged], or widowed). It does not include incest, homosexuality, bestiality, prostitution, harlotry, etc., nor does it include adultery.
If this word was inclusive of all sorts of sexual acts, as many unfortunately believe and teach, it becomes very problematic. First of all, if porneia includes adultery, then why are there so many passages where both Greek words are used side by side (Matt. 15:19; Mark 7:21; Gal. 5:19; 1 Cor. 6:9; Heb. 13:4)? This becomes rather redundant. Second of all, if porneia includes other sexual acts, such as homosexuality, then, again, why are both words used side by side (1 Cor. 6:9)? Again, it would be rather redundant. When this word is understood correctly, it keeps us accountable for our actions and restricts our behaviour.
The Bible uses the terms adultery and fornication to address both physical and spiritual sin. When speaking of physical sin, adultery is illicit sexual acts committed by married persons (currently married or previously married [divorced]), while fornication is illicit sexual acts committed by unmarried persons (single, betrothed [engaged], or widowed). Adultery is only applicable to married persons, while fornication is only applicable to unmarried or single persons. When speaking of spiritual sin, spiritual adultery is the act of seeking after signs by unbelievers, while spiritual fornication is the act of seeking after signs by believers. The act of adultery and the act of fornication are identical. Likewise, the act of spiritual adultery and the act of spiritual fornication are identical.
Here is a biblical look at spiritual adultery:
Then some of the scribes and Pharisees answered, saying, "Teacher, we want to see a sign from You." But He answered and said to them, "An evil and adulterous generation seeks after a sign, and no sign will be given to it except the sign of the prophet Jonah. Matthew 12:38-39
Then the Pharisees and Sadducees came, and testing Him asked that He would show them a sign from heaven. He answered and said to them, "When it is evening you say, "It will be fair weather, for the sky is red"; and in the morning, "It will be foul weather today, for the sky is red and threatening." hypocrites! You know how to discern the face of the sky, but you cannot discern the signs of the times. A wicked and adulterous generation seeks after a sign, and no sign shall be given to it except the sign of the prophet Jonah." And He left them and departed. Matthew 16:1-4
"For false christs and false prophets will rise and show great signs and wonders to deceive, if possible, even the elect." Matthew 24:24
Then the Pharisees came out and began to dispute with Him, seeking from Him a sign from heaven, testing Him. But He sighed deeply in His spirit, and said, "Why does this generation seek a sign? Assuredly, I say to you, no sign shall be given to this generation." . . . For whoever is ashamed of Me and My words in this adulterous and sinful generation, of him the Son of Man also will be ashamed when He comes in the glory of His Father with the holy angels." Mark 8:11-12, 38
Others, testing Him, sought from Him a sign from heaven. Luke 11:16
So the Jews answered and said to Him, "What sign do You show to us, since You do these things?" John 2:18
Then Jesus said to him, "Unless you people see signs and wonders, you will by no means believe." John 4:48
Therefore they said to Him, "What sign will You perform then, that we may see it and believe You? What work [Miracle] will You do? John 6:30
Then the chief priests and the Pharisees gathered a council and said, "What shall we do? For this Man works many signs [Miracles]. John 11:47
But although He had done so many signs before them, they did not believe in Him, John 12:37
Spiritual adultery = an evil generation (Matt. 12:39), a wicked generation (Matt. 16:4), a sinful generation that rejects the Word of God (Mark 8:11-12, 38), hypocrites (Matt.16:1-3), deception (Matt. 24:24), and unbelievers (John 4:48). In Luke 11:29-32, Jesus contrasts spiritual adultery with the wisdom of Solomon, the preaching of Jonah, and His own teachings.
If the church understood the Doctrine of Fornication correctly, and believed it earnestly, it would not be in the condition it is today. Marriages would not be in ruin due to false teachers teaching lies that contradict the truths of Scripture. Matthew 5:32 and 19:9 do not say "except for adultery," as is taught and believed by a vast majority of professing believers—unfortunately, but rather "except for fornication." Every time Jesus spoke of adultery, He used the Greek word moicheia. But when He says, "except for," He uses the Greek word porneia. In other words, if Jesus intended to say "except for adultery," He would have used the word moicheia. But He did not! Any Christian who believes and teaches that these verses allow for divorce is a liar and a false teacher! If you are offended by my saying this, good! You deserve a wake-up call. I suggest cracking your Bible and studying it a little more closely and a lot more in depth.
Marriage is my reformation, and I will strive to teach Christians the truth of this sacred institution until we take it back and look at it soberly and honourably, holding it in the highest regard (Heb. 13:4). Marriage is a divine institution and the cost must be counted before entering into it. If you cannot treat it the way it demands to be treated, then you ought not to marry because divorce is not an option!