It's helpful to know that the actual scripture does not refer to a vague, uncertain thing like our modern word 'gay' or even our modern word 'homosexual' in the literal text (in literal translations I've seen), but instead to a precise action, intercourse sodomy, only, and not other things which people like to add in today, against scripture (adding to scripture is prohibited in scripture). You you can learn this by reading the scripture carefully. Here's the ESV (an excellent and accurate) translation:
Leviticus 18 ESV
verse 22 is the one so many people don't realize the wording of, which isn't 'gay' or even 'homosexual' accurately, but instead intercourse sodomy alone, leaving all the other various gay interactions completely ok (unless we try to add to scripture new things not in it).
If anyone is unsure of the verb meaning (intercourse) in verse 22, then examine verse 23 to ascertain the accurate meaning of the verb.
Notice how this real scriptural wording isn't so comfortable for all traditional man/woman married couples, who have in reality some of them done this very thing themselves....
From this accuracy, we can see the Bible says nothing against gay marriage in Lev 22, the chapter on sexual sins.
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"Thou shalt not lie with mankind, as with womankind: it is abomination." (Lev 18:22, KJV)
"These are the statutes and judgments and laws, which the LORD made between him and
the children of Israel in mount Sinai by the hand of Moses." (Lev 26:46, KJV)
"These are the commandments, which the LORD
commanded Moses for the children of Israel in mount Sinai." (Lev 27:34, KJV)
God's law, the law of the Son of God exists from Genesis onward, never abolished; Jesus Christ abolished the law of Moses, nailing it to his cross. Christians are under the New Covenant, not the Old Covenant. Those of us who are Gentiles were NEVER under the law of Moses.
"Thou shalt not avenge, nor bear any grudge against the children of thy people,
but thou shalt love thy neighbour as thyself: I am the LORD." (Lev 19:18, KJV)
The underlined is for New Covenant believers, NOT because it is in Leviticus; but it is quoted exactly, word for word for New Covenant believers 6 times.
Bible scholars have known for centuries that Lev. 18:22 is referring to cult prostitutes, the ritual prostitution of idolaters. The Hebrew
chuqqah, which the KJV renders "ordinances" in 18:3; and
to ebah, which the KJV renders "abomination" in 18:22 are both words used with religious ritual.
In the Tyndale Old Testament Commentary series, Leviticus, by Professor R. K. Harrison, the commentary on v22 reads:
"The regulations of Leviticus condemn certain aberrations found among the Egyptians and Canaanites, who went far towards deifying sexual activity, and assigned the title 'holy ones' to cultic prostitutes. Sacro-homosexual practices and female prostitution within the context of the cultus was probably well established throughout the ancient Near East long before the Israelites occupied Canaan. Homosexuality of a non-religious variety is poorly documented in Mesopotamian texts..." page 191
On the last page of the commentary, page 252 he states: "For a person to think of himself or herself as a 'Christian homosexual' or a 'Christian lesbian' is a complete contradiction in terms..."
He is obviously NOT a liberal, gay-friendly professor, promoting homosexuality.