'Oath' in the Bible

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

If any man trespass against his neighbour, and an oath be laid upon him to cause him to swear, and the oath come before thine altar in this house:

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