And he said in answer, have you not seen in the writings, that he who made
them at the first made them male and female, and said, for this cause will
a man go away from his father and mother, and be joined to his wife; and the
two will become one flesh? So that they are no longer two, but one flesh. Then
let not that which has been joined by God be parted by man. Matthew 19 : 4-6



Marriage : Some practical cases


They say to him, why then did Moses give orders that a husband might give her a
statement in writing and be free from her? He says to them, Moses, because of your
hard hearts, let you put away your wives: but it has not been so from the first.  And I
say to you, whoever puts away his wife for any other cause than the loss of her virtue,
and takes another, is a false husband: and he who takes her as his wife when she is put
away, is no true husband to her. The disciples say to him, If this is the position of a man
in relation to his wife, it is better not to be married. But he said to them, not all men
are able to take in this saying, but only those to whom it is given.
Matthew 19 : 7 - 11