Thematic Bible: Why moses allowed divorce

They said to him, "Why then did Moses command us to give a certificate of dismissal and to divorce her?" Jesus said to them, "Moses permitted you to divorce your wives because of your hard hearts, but from the beginning it was not this way.

Then some Pharisees came, and to test him they asked, "Is it lawful for a man to divorce his wife?" He answered them, "What did Moses command you?" They said, "Moses permitted a man to write a certificate of dismissal and to divorce her." read more.
But Jesus said to them, "He wrote this commandment for you because of your hard hearts. But from the beginning of creation he made them male and female.