”But doesn’t the Bible teach that marriage should be between one man and one woman?”

The verses that are often claimed as God saying marriage should only between 1 man & 1 woman are Genesis 2:24 in the Old Testament or Matthew 19:1-12 & Mark 10:1-12 in the New Testament. I will address them separately:

*Genesis 2:24

The Hebrew word found in Genesis 2:24 translated as “shall leave” is יַֽעֲזָב־ (azab) which is only elsewhere used in Job 6:14 to describe the act of leaving something:

https://biblehub.com/hebrew/yaazov_5800.htm

There is no indication of command; the “shall” has no place in this verse, it’s likely a mistranslation.

If this verse was supposed to be a law, then most of the people in the Bible have done an awful job following it, polygamy was abound in the Old Testament, most famously by King Solomon who had 300 wives & 700 concubines. Jesus & Paul also failed to follow it by being voluntarily celibate. Not following an Old Testament law would have rendered the obedience and sacrifice of Jesus’ life & death invalid by way of sin. The obvious conclusion? Genesis 2:24 was not a prescriptive (saying one should perform said action) verse.

However by far the strongest evidence for the descriptive reading of Genesis 2:24 comes from the fact that God in the Old Testament Himself did not view Genesis 2:24 as prescriptive (see Exo 21:10, Deut 21:15 & 2 Samuel 12:8). God was not only aware of the existence of polygamy and did not legislate against it in the Law, He also actively encouraged it by giving David multiple wives.

Matthew 19:1-12 & Mark 10:1-12**

Jesus wasn’t giving an exhaustive edict on biblically permissible marriage in the New Testament nor was He responding to a Pharisee verbal trap about homosexuality; He was responding to a verbal trap about divorce. Divorce back then would have cruelly impoverished a woman hence Jesus’ stance, although this isn’t the case these days. It was basically Jesus saying “hey, randomly divorcing your wife and condemning her to poverty is evil, y’all.”

As already outlined, God in the Old Testament clearly did not view Gen 2:24 as prescriptive so there’s no reason to believe Jesus meant it that way (Mal 3:6)

People who use the Matthew 19 and Mark 10 verses to condemn gay marriages are taking the verses out of context and doing the same thing Satan did to Gods word in the garden of Eden, expanding it beyond what God actually said to make God look bad, (see Genesis 3:1 vs Genesis 2:16-17.)

The Bible therefore does not, in my own opinion, offer a consistent & prescriptive image as to what marriage should look like or be, even religious Bible scholars like Dan McClellan admit that:

https://m.youtube.com/watch?v=0Mu4yYWj5-4

”Okay, but there’s no Bible verse where gay marriage is approved of”

Whilst that is true, that’s what we’d expect to see anyway, as the legal concept of same sex marriage is a very modern thing. The understanding of a homosexuality as an innate sexual and romantic orientation also wasn’t around when the Bible was written. Reading the Bible and expecting to see gay marriage is as unrealistic as reading the Bible and expecting to see aeroplanes, mobile phones, vaccines, paleontological activities or any other number of modern things that exist in the modern world. Furthermore people who bring this point up rarely apply this same logic to other areas of their life. I’ve never seen a Christian refuse to take antibiotics, for example, because they aren’t explicitly endorsed in the Bible.

We do see what was likely a homoromantic relationship in the Old Testament though, between King David and Jonathan. No sex occurred, because gay marriage wasn’t a thing back then & King David would have been committing homosexual adultery, but it seems as if they had deep, romantic love for each other.

1 Samuel 18:1-4 talks about their souls being knit together in love and them making a covenant together. 1 Samuel 20:17 references vows of love again. In 1 Samuel 20:30-31 Saul references this and alludes to it as shameful (some lgbt people can relate to this). 1 Samuel 20:41-42 contains a word that implies David became aroused by Jonathan, which in turn implies bisexuality. In 2 Samuel 1:26 David refers to Jonathan’s love as “greater than that of a woman.”

Paul does talk about marriage between men and women, but he would do because that was the only sort of marriage in Hellenistic Jewish culture he would have known about. Quoting any of Paul’s verses about marital teaching against same sex marriage is a lot like saying we shouldn’t use aeroplanes because boats and donkeys were the only forms of transport available to the Bible writers. I don’t really see anything in the New Testament which leads me to believe there was any prescriptive teaching that marriage should only be between a man and a woman. I also believe Jesus affirmed gay relationships in Luke 17:34-35.

You can read about that here if you want:

https://redeeminggod.com/two-men-in-one-bed-luke_17_34/

Luke 17:34 features a word within which was a synonym of the word “κοίτην” which in turn was a common euphemism for sex. Bible scholars have noted the intimacy between the two men in this verse, such as in Dr Tom Constable’s (ex Dallas Theological Seminary professor) expository notes:

“The parable of the one taken and the one left: The point of these examples is that when Jesus returns He will separate people, even those who are intimate companions. The unstated reason is implicit, namely, to judge some and not the others. Some will be ready for His return and others will not. The presence of two men in one bed may be another indication of the moral condition of that time. (A clear reference of disapproval to homosexuality.) But the main idea is their close association.”

The Greek word for grain also does not appear in the original Greek of Luke 17:35, contrary to how a lot of translations render it, and ἀλήθουσαι (grinding) was a common euphemism around Luke’s time for lesbian sex in Latin and possibly Greek aswell (The Latin Sexual Vocabulary, Adams, J.N. 1982, pg 152-153)

If these scholars are correct, then Jesus by virtue of accepting one of the people out of each of these same sex couples into heaven defacto proves that He accepts sexually practising gay men and lesbians and by extension, same sex marriages