Mark 10:2-9

And there came unto him Pharisees, and asked him, Is it lawful for a man to put away his wife? trying him. And he answered and said unto them, What did Moses command you? And they said, Moses suffered to write a bill of divorcement, and to put her away. But Jesus said unto them, For your hardness of heart he wrote you this commandment. But from the beginning of the creation, Male and female made he them. For this cause shall a man leave his father and mother, and shall cleave to his wife; and the two shall become one flesh: so that they are no more two, but one flesh. What therefore God hath joined together, let not man put asunder.