Meaning: Marriage is not to be disolved by human authority.
Matthew 19:3-6
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.
Mark 10:9
What therefore God hath joined together, let not man put asunder.