What does Matthew 19:5 mean?

Jesus is answering a question from some Pharisees who are testing Him and trying to trip Him up. They want Him to say something controversial about the highly divisive issue of divorce. They hope any answer He gives will damage His popularity and, perhaps, give them cause to call Him a heretic (Matthew 19:1–4).

Jesus quoted from Genesis 1:27 in the previous verse, that God created people male and female. Now Jesus quotes from Genesis 2:24, which speaks of a man and woman becoming bound together in a marriage. Jesus, of course, knows the Pharisees have read these passages. His point is that those who treat divorce lightly do not value what God has revealed to them.

This point will be driven home in the following verse. Already, though, Jesus shows that God established marriage from the very beginning of creation. It is built into the design of humanity as men and women. Marriage is more than two people coming alongside each other to do life together; it is the union of two people into one flesh. This happens, in part, through sex, but also through the commitment built into the marriage connection.

Because that is true, what does it mean for breaking that union in divorce? Jesus reveals God's heart in the following verse.