Mark 10:6-12

But from the beginning God created male and female. For this reason a man will leave his parents and be wedded to his wife. And the husband and wife will be joined as one flesh, and after that they no longer exist as two, but one flesh. So there you have it. What God has joined together, no one has the right to split apart.” Once indoors, his disciples asked him to explain it to them again. So he said to them, “Whoever divorces his wife and marries another commits adultery against her. And if the wife divorces her husband and marries another, she also commits adultery.”