Is sex before marriage really something that God said was wrong in the Bible?

Yes, biblically-speaking. Depends if you assume the bible to be true - as a Christian I do.

Answer

Yes, in Galatians 5:19 -21. Fornication is the word used for sex before marriage.

Galatians 5:19-21 (King James Version)

19Now the works of the flesh are manifest, which are these; Adultery, fornication, uncleanness, lasciviousness, 20Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies,21Envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God.
  1. Hebrews 13:4 (New International Version)

    Marriage should be honored by all, and the marriage bed kept pure, for God will judge the adulterer and all the sexually immoral.

  2. Proverbs 18:22 (New International Version)

    He who finds a wife finds what is good and receives favor from the LORD.

  3. Galatians 5:19-22 (New International Version)

The acts of the sinful nature are obvious: sexual immorality, impurity and debauchery; idolatry and witchcraft; hatred, discord, jealousy, fits of rage, selfish ambition, dissensions, factions and envy; drunkenness, orgies, and the like. I warn you, as I did before, that those who live like this will not inherit the kingdom of God.

Which you can see says nothing of sex before marriage, thus not providing an adequate answer for the question. "Sexual immorality" can be taken many different ways even if you "use a dictionary".

The meaning of the original Greek word, porneia, is used generally in the texts for premarital sex, adultery etc.

Opinion

Marriage is just a ritual invented by men to legitimize the Husband's claim to the wife as his possession. Adam and Eve's relationship was not ritualized by marriage.

I cannot recall any verses that "God said" in answer to your question.

Answer

The institution of marriage as it is known in the western world has its origins in Genesis, the original marriage of the first man and woman being reiterated by Jesus when He stated' therefore a man shall leave His father and mother and be joined to his wife and the two shall be one flesh'. This, although not accompanied by all the trappings now added to marriage ceremonies, was certainly one in every sense of the word and forms the basis of the Biblical understanding of marriage. Only after they were married did Adam and Eve have sex as indicated also in Genesis - '...and Adam knew his wife.' The Hebrew word translated 'know' in the KJV clearly means sexual intercourse.

This understanding of the proper place of sex as being within marriage continues through the Old Testament into the New.

Additional Comments:

No- it is what man has determined the Bible to say, and words have changed meaning. The word fornication had nothing to do with sex originally. It had to do with idol worship.

No. Contrary to popular belief, the word "fornication" in the Bible does not mean "sex before marriage". The greek word used is "porneia", and it refers to every kind of sex that is forbidden in the Old Testament. For example "adultery" is "porneia". A good example of this is in 1 Corinthians 5:1. the verse says "It is reported commonly that there is fornication among you, and such fornication as is not so much as named among the Gentiles, that one should have his father's wife.". Notice that this act of "fornication" does not refer to "sex before marriage", but rather forbidden relations between a man and his father's wife. This relationship is forbidden in the Old Testament. Many bible translate "porneia" as "sexual immorality", which is more accurate than "fornication". The word "fornication" is a bad translation to begin with, since it refers solely to the act of prostitution, by it's latin root. Only outdated translations like KJV will use the incorrect "fornication". Contrary to popular belief, there is no verse anywhere, Old or New testament, that says that sex before marriage is a sin. However, the Old Testament states that if a man seduces a lady and sleeps with her, he is obligated to marry her, unless she or her father refuse, but the option for her to marry him must be there (exodus 22:16-17). In most religions, it is encouraged to marry the one that a person sleeps with, which has advantages, such as the case of resulting in child birth, then the child may have two parents and financial reasons as well, but as far as "does the bible say it is a sin", no it does not, but biblically, one is bound to offer marriage after the act.