Matthew 19:5

³  The Pharisees also came unto him, tempting him, and saying unto him, Is it lawful for a man to put away his wife for every cause?

⁴  And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female,

⁵  And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh?

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

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