'Swear by God' in the Bible

And he also rebelled against king Nebuchadnezzar, who had made him swear by God: but he stiffened his neck, and hardened his heart against turning unto Jehovah, the God of Israel.

And I contended with them, and cursed them, and smote certain of them, and plucked off their hair, and made them swear by God,'saying , Ye shall not give your daughters unto their sons, nor take their daughters for your sons, or for yourselves.