'Oath' in the Bible

And so, because he was a prophet and knew that God had sworn to him with an oath to seat one of his descendants on his throne,

When it was day, the Jews formed a conspiracy and bound themselves under an oath, saying that they would neither eat nor drink until they had killed Paul.

They came to the chief priests and the elders and said, “We have bound ourselves under a solemn oath to taste nothing until we have killed Paul.