Some Pharisees1 came and tested him by asking, "Is it lawful for a man to divorce his wife?"
"What did Moses command you?" he replied.
They said, "Moses permitted a man to write a certificate of divorce and send her away."2
"It was because your hearts were hard3 that Moses wrote you this law," Jesus replied.
"But at the beginning of creation God 'made them male and female.'4
'For this reason a man will leave his father and mother and be united to his wife,
and the two will become one flesh.'5 So they are no longer two, but one.
Therefore what God has joined together, let man not separate."
When they were in the house again, the disciples asked Jesus about this.
He answered, "Anyone who divorces his wife and marries another woman commits adultery against her.6
References for Mark 10:11
And if she divorces her husband and marries another man, she commits adultery."7
References for Mark 10:12