'Oath' in the Bible

Why then hast thou not kept the oath of Jehovah, and the commandment that I charged thee with?

If a man have sinned against his neighbour, and an oath be laid upon him to adjure him, and the oath come before thine altar in this house;

As Jehovah thy God liveth, there is no nation or kingdom whither my lord has not sent to seek thee; and when they said, He is not here, he took an oath of the kingdom or nation that they found thee not.