'Swear' in the Bible

And Samson said to them, "If this is what you do, I swear I will be avenged upon you, and after that I will quit."

And they said to him, "We have come down to bind you, that we may give you into the hands of the Philistines." And Samson said to them, "Swear to me that you will not fall upon me yourselves."