In the first book of the Bible, God reveals to mankind the way in which He created the world, His relationship to it, and the relationships within it. The record starts with a simple statement, Genesis 1:1-2, “In the beginning God created the heavens and the earth. Now the earth was formless and empty, darkness was over the surface of the deep, and the Spirit of God was hovering over the waters.”
What follows is the same account told (in the nature of Hebrew history) twice more, once from an overall perspective and again focusing on the first humans. The pinnacle of that act of creation was the first marriage, Genesis 2:22-25
Then the LORD God made a woman from the rib he had taken out of the man, and he brought her to the man.
The man said, “This is now bone of my bones and flesh of my flesh; she shall be called ‘woman,’ for she was taken out of man.”
For this reason a man will leave his father and mother and be united to his wife, and they will become one flesh. The man and his wife were both naked, and they felt no shame.
In creating marriage, God was not creating a substance, like matter, bound by unchangeable physical laws, but He was creating something that He intended to remain unchanged, even as Jesus says, Matthew 19:4-6, “Haven’t you read,” he replied, “that at the beginning the Creator ‘made them male and female,’ and said, ‘For this reason a man will leave his father and mother and be united to his wife, and the two will become one flesh’? So they are no longer two, but one. Therefore what God has joined together, let man not separate.”
Marriage is not an institution that we can really change. It is what God made it and can only be perverted, not changed.
It is worth considering that as Jesus reveals himself to his disciples it is as a person of the Trinity in His baptism, and as the one who blesses marriage at the wedding of Cana. So He has come to redeem what was lost, and to remake what was broken.