Consider that the Bible doesn't always explain things using the same words that we would use. For example, we sometimes talk about "the Trinity" or "the Second Coming" as if these are Biblical phrases, but actually the Bible never uses these terms (even though these concepts are clearly taught in Scripture, as I have shown in some of my other articles). Therefore, it's important that we try to look at the greatest weight of evidence in order to find out what the New Testament reveals about God's will concerning premarital sex, even if the Bible never uses the words "premarital sex."
First, notice how strongly the New Testament speaks out against sexual sins:
"Flee from sexual immorality. All other sins a man commits are outside his body, but he who sins sexually sins against his own body. Do you not know that your body is a temple of the Holy Spirit, who is in you, whom you have received from God? You are not your own; you were bought at a price. Therefore honor God with your body." (1 Corinthians 6:18-20)
"But among you there must not be even a hint of sexual immorality, or of any kind of impurity, or of greed, because these are improper for God's holy people." (Ephesians 5:3)
The above passages tell us to flee from sexual immorality and not allow even a hint of sexual immorality in our lives. These are strong words, so it is important that we make the right decision about premarital sex.
Now notice some more ways that God condemns sexual immorality:
"Do you not know that the wicked will not inherit the kingdom of God? Do not be deceived: Neither the sexually immoral nor idolaters nor adulterers nor male prostitutes nor homosexual offenders nor thieves nor the greedy nor drunkards nor slanderers nor swindlers will inherit the kingdom of God." (1 Corinthians 6:9-10)
"We should not commit sexual immorality, as some of them did--and in one day twenty-three thousand of them died." (1 Corinthians 10:8)
"Marriage should be honored by all, and the marriage bed kept pure, for God will judge the adulterer and all the sexually immoral." (Hebrews 13:4)
"But the cowardly, the unbelieving, the vile, the murderers, the sexually immoral, those who practice magic arts, the idolaters and all liars-- their place will be in the fiery lake of burning sulfur. This is the second death." (Revelation 21:8)
These passages say that the "sexually immoral" will not inherit the kingdom of God, but instead they will be judged and will be sent to the fiery lake of burning sulfur. Christians will not be sent to the fiery lake of burning sulfur, but the above passages give us a very clear idea of the heart of God concerning sexual immorality. God has a strong view of any kind of immorality, so we should try to err on the side of purity. For example, the apostle Paul said that the Church will be presented to Christ as a pure virgin bride:
"I am jealous for you with a godly jealousy. I promised you to one husband, to Christ, so that I might present you as a pure virgin to him." (2 Corinthians 11:2)
This indicates that purity and virginity are highly valued before marriage in Scripture. Premarital sex takes away that purity and virginity. For those who have already lost that purity before marriage, God is willing to forgive our sins and purify us from all unrighteousness (1 John 1:9). As Christian recording artist Rebecca St. James says, if we have made the mistake of having sex before marriage then we can repent and give our sexuality back to God and become "recycled virgins." As I see it, the idea of being a "recycled virgin" means that we have received forgiveness from God and we are now keeping ourselves pure for marriage without having premarital sex anymore (just like a virgin).
Notice that the apostle Paul said that if unmarried people cannot control their sexual desires then they should get married:
"Now to the unmarried and the widows I say: It is good for them to stay unmarried, as I am. But if they cannot control themselves, they should marry, for it is better to marry than to burn with passion [literally, "be inflamed (with anger, grief, lust)" - see Strong's Greek Dictionary]." (1 Corinthians 7:8-9)
The above passage says that if unmarried people are not able to be celibate (as Paul was) and they find themselves burning with sexual desire, then they should get married in order to avoid committing any sexual sins. This means that sex outside of marriage is a sin, as the following passage also indicates:
"Now concerning the things whereof ye wrote unto me: It is good for a man not to touch a woman [or, "It is good for a man not to have sexual relations with a woman," according to the NIV footnote]. Nevertheless, to avoid fornication, let every man have his own wife, and let every woman have her own husband." (1 Corinthians 7:1-2, KJV)
In the above passage, notice that Paul had a very specific reason why people should get married: "to avoid fornication." Here is what the English word "fornication" means:
"to have sex with someone who you are not married to" (Freesearch Dictionary )
"Fornication: Sexual intercourse that is "illicit", outside of marriage." (Medical Dictionary )
"fornication n. sexual intercourse between a man and woman who are not married to each other." (Law Dictionary )
"consensual sexual intercourse between two persons not married to each other" (Merriam-Webster Online Dictionary )
"NOUN: Sexual intercourse between partners who are not married to each other.
WORD HISTORY: The word fornication had a lowly beginning suitable to what has long been the low moral status of the act to which it refers. The Latin word fornix, from which fornicti, the ancestor of fornication, is derived, meant "a vault, an arch." The term also referred to a vaulted cellar or similar place where prostitutes plied their trade. This sense of fornix in Late Latin yielded the verb fornicr, "to commit fornication," from which is derived fornicti, "whoredom, fornication." Our word is first recorded in Middle English about 1303." (The American Heritage� Dictionary of the English Language: Fourth Edition. 2000. )
"c.1300, from O.Fr. fornication, from L.L. fornicationem (nom. fornicatio), from fornicari "fornicate," from L. fornix (gen. fornicis) "brothel," originally "arch, vaulted chamber" (Roman prostitutes commonly solicited from under the arches of certain buildings), from fornus "oven of arched or domed shape." Strictly, "voluntary sex between an unmarried man and an unmarried woman;" extended in the Bible to adultery." (Online Etymology Dictionary )
When Bible translations, Bible commentaries, etc., use the English word "fornication," the primary meaning of this word is voluntary sex between an unmarried man and an unmarried woman. As we can see in the definitions above, the word "fornication" has had the basic meaning of "prostitution, premarital sex" since the 1300's (which was before the KJV was written in 1611). "Fornication" is the word which many Bible scholars use for translating the Greek word porneia into English when the Scriptural context is describing premarital sex. According to various Greek dictionaries and Bible commentaries, here is what the Greek word porneia means:
"harlotry (including adultery and incest); figuratively idolatry: - fornication." (Strong's Greek Dictionary , emphasis added)
"porneia:
1) illicit sexual intercourse
1a) adultery, fornication, homosexuality, lesbianism, intercourse with animals etc.
1b) sexual intercourse with close relatives; Lev. 18
1c) sexual intercourse with a divorced man or woman; Mar_10:11,Mar_10:12
2) metaphorically the worship of idols
2a) of the defilement of idolatry, as incurred by eating the sacrifices offered to idols" (Thayer's Greek Dictionary , emphasis added)
Is Premarital Sex A Sin?