Honor Marriage
Have you not read that the one who made them at the beginning 'made them male and female,' and said, 'For this reason a man shall leave his father and mother and be joined to his wife, and the two shall become one flesh'? So they are no longer two but one flesh. Therefore what God has joined together, let no one separate.
Matthew 19:4-6
Tested with a divorce question, Jesus reached past Moses back to the beginning: what God has joined together, let no one separate.
Jesus grounds marriage not in contract or culture but in creation, a joining God himself performs. One flesh means the union is not a partnership of two parties but a new single thing, and tearing it is tearing something living.
If you are married, guard the joining like the sacred thing it is: tend it daily, defend it from small erosions, and let no one, including you, treat separation as casual. If you are not, honor others' marriages with your conduct and your words.