Same-sex marriage is rejected as un-Christian and immoral on the basis of a myopic reading of a very few Biblical texts. And the texts in question are scant indeed. The most referenced texts are Genesis 19; the holiness codes of Leviticus 17-26, and in the New Testament, Paul's First Letter to the Corinthians 6:9 and his Letter to the Romans 1:26-27. Not only does one have to "hunt" for references to same-sex practices, but there are no gospel texts that treat the matter. There is nothing attributed to Jesus of Nazareth that has anything to do with same-sex orientation.
According to the gospels, Jesus never commented on same-sex practices; that fact certainly bears repeating to anyone criticizing the gay community on Christian grounds. Largely, same-sex practice is a topic of little interest to the Biblical authors. The Biblical texts that are most often cited in the same-sex debate deserve some explanation in order to reduce their citation for hurtful purposes. For example, the text of Genesis 19 centers upon the story of Lot's visitation in the city of Sodom by two angels. The men of Sodom tell Lot to hand over the male visitors so that they may "know" them, i.e. sexually know them (giving rise to the term "sodomy"). Lot bargains with the visitors, quite horribly to a contemporary reader's eyes, by offering the men his virgin daughters instead. However, any reader of ancient literature (of which the Hebrew Bible is a component) would realize the familiar motif concerning hospitality. For example, the Greek gods Zeus and Hermes would frequently disguise themselves as humans in order to ferret who among their supplicants were truly hospitable. The story is not one denigrating same-sex practice; instead it upholds the incredible (and ludicrous) hospitality of Lot as a virtue.
Similarly, the holiness codes of Leviticus thread down from an all-encompassing mandate to behave distinctly from their foreign (and depraved) neighbors. Leviticus 20:13 that proscribes the death penalty for same-sex relations is quite related to codes that condemn bestiality, invoke dietary restrictions, and order the wearing of certain fibers. The codes make the Israelites unique from their neighbors, and they reflect a particular time and place in Israelite history. Any contemporary critique must note this reality before invoking the codes as ammunition against same-sex practice.
Fourth, any reference to same-sex practice by a Biblical writer or a Greco-Roman writer has no knowledge or understanding of the concept of "same-sex orientation." There is no Hebrew or Greek cognate word in the Biblical text to reflect the modern term "same-sex orientation" or "homosexuality." Moreover, there were no discussions or arguments concerning sexual orientation in the ancient and late ancient world, conversations that would only arrive in the modern era of psychology. Instead, ancient writers believed any wanton sexual behavior of any variety is a mismanagement of one's appetites. The apostle Paul, in the New Testament, follows this pattern.
The Pauline letters that are raised in the same-sex debate are part of Paul's understanding of sexual immorality in the first century CE. In his letter to the Corinthians, Paul includes in a laundry list of vices "male prostitutes" and "sodomites" (as
malakoi and
arsenokoitai are translated by the NRSV; 1 Cor 6:9). These terms are injected along with many other vices: "fornicators, idolaters, adulterers," and Paul is addressing the issue of a church member sleeping with his stepmother. In other words, Paul is addressing ALL deviant sexual and immoral behavior, not just that of a same-sex variety. In his address to the Romans, Paul describes the root sin of the Gentiles as idolatry, and the consequences of idolatry are vices beginning with women and men "exchanging" natural intercourse for unnatural. While Paul is describing this behavior as the result of wayward passions, the chief sin is idolatry and separation from the one true God. While the Romans text offers the longest discussion of same-sex behavior in the New Testament, it is unclear whether it truly is a condemnation of a specific practice.
http://www.huffingtonpost.com/lee-jefferson/bible-gay-marriage_b_886102.html