Mark 10:2-12.

Mark 10:2-12 [2]Some Pharisees came up to Jesus, testing Him, and began to question Him whether it was lawful for a man to divorce a wife. [3]And He answered and said to them, "What did Moses command you?" [4]They said, "Moses permitted a man to write a certificate of divorce and send her away." [5]But Jesus said to them, "Because of your hardness of heart he wrote you this commandment. [6]But from the beginning of creation, God made them male and female. [7]For this reason a man shall leave his father and mother, [8]and the two shall become one flesh; so they are no longer two, but one flesh. [9]What therefore God has joined together, let no man separate." [10]In the house the disciples began questioning Him about this again. [11]And He said to them, "Whoever divorces his wife and marries another woman commits adultery against her; [12]and if she herself divorces her husband and marries another man, she is committing adultery."