Matthew
Matthew 19:8BSB·traditional attribution

Jesus replied, “Moses permitted you to divorce your wives because of your hardness of heart. But it was not this way from the beginning.

John Gill Reformed Baptist @doctorgill

He saith unto them,.... In answer to their objection; Moses, because of the hardness of your hearts, suffered you to put away your wives: in which may be observed, that, though it was by direction that Moses, in his system of laws, allowed of divorces; yet not God, but he is said to do it, because it was a branch of the political and judicial...

Albert Barnes Presbyterian @notesbybarnes

Verse 8. He saith unto them, etc. Jesus admits that this was allowed; but still he contends that this was not the original design of marriage. It was only a temporary expedient, growing out of a peculiar state of things, and not designed to be perpetual. It was on account of the hardness of their hearts. Moses found the custom in use. He found a hard-hearted and rebellious people.

Jamieson-Fausset-Brown Reformed @jfbcommentary

He saith unto them, Moses--as a civil lawgiver. because of--or "having respect to." the hardness of your hearts--looking to your low moral state, and your inability to endure the strictness of the original law. suffered you to put away your wives--tolerated a relaxation of the strictness of the marriage bond--not as approving of it, but to prevent still greater evils.