What does the Bible say about gay marriage / same sex marriage?
While the Bible does address homosexuality, it does not explicitly mention gay marriage/same-sex marriage. It is clear, however, that the Bible condemns homosexuality as an immoral and unnatural sin. Leviticus 18:22 identifies homosexual sex as an abomination, a detestable sin. Romans 1:26-27 declares homosexual desires and actions to be shameful, unnatural, lustful, and indecent. First Corinthians 6:9 states that homosexuals are unrighteous and will not inherit the kingdom of God. Since both homosexual desires and actions are condemned in the Bible, it is clear that homosexuals “marrying” is not God’s will, and would be, in fact, sinful.
Whenever the Bible mentions marriage, it is between a male and a female. The first mention of marriage, Genesis 2:24, describes it as a man leaving his parents and being united to his wife. In passages that contain instructions regarding marriage, such as 1 Corinthians 7:2-16 and Ephesians 5:23-33, the Bible clearly identifies marriage as being between a man and a woman. Biblically speaking, marriage is the lifetime union of a man and a woman, primarily for the purpose of building a family and providing a stable environment for that family.
READ MORE: http://www.gotquestions.org/gay-marriage.html