Matthew 19:6

3 And there came unto him Pharisees, trying him, and saying, Is it lawful [for a man] to put away his wife for every cause?

4 And he answered and said, Have ye not read, that he who made [them] from the beginning made them male and female,

5 and said, For this cause shall a man leave his father and mother, and shall cleave to his wife; and the two shall become one flesh?

6 So that they are no more two, but one flesh. What therefore God hath joined together, let not man put asunder.

7 They say unto him, Why then did Moses command to give a bill of divorcement, and to put [her] away?

8 He saith unto them, Moses for your hardness of heart suffered you to put away your wives: but from the beginning it hath not been so.

9 And I say unto you, Whosoever shall put away his wife, except for fornication, and shall marry another, committeth adultery: and he that marrieth her when she is put away committeth adultery.