Mark 10:8 in the World English Bible
and the two will become one flesh, so that they are no longer two, but one flesh.
Context
7 For this cause shall a man leave his father and mother, and cleave to his wife;
8 And they twain shall be one flesh: so then they are no more twain, but one flesh.
9 What therefore God hath joined together, let not man put asunder.