Mark 10:4

And they said
By way of reply,

Moses suffered to write a bill of divorcement, and to put her away,
Moses did not command them to divorce their wives, only suffered them to do so: and gave orders that if they could not bear that they should live with them, but would divorce them, that they should give them a bill, which should certify, they were so divorced, and then send them out of their houses, free to marry other men; this law, or permission, is in ( Deuteronomy 24:1 ) , of the form of a bill of divorcement, (See Gill on Matthew 5:31).