Matthew 5:31

It used to be said, Whoever divorces his wife must give her a divorce-certificate.

They said to him, "Then why did Moses lay it down that we were to divorce by giving a separation-notice?"

Then the Pharisees came up to tempt him. They asked, "Is it right to divorce one's wife for any reason?"

Now some Pharisees came up and asked him if a man was allowed to divorce his wife. This was to tempt him.

Treasury of Scripture Knowledge

It hath been said, Whosoever shall put away his wife, let him give her a writing of divorcement:

They said, "Moses permitted a man to divorce her by writing out a separation notice."