Matthew 5:34-37

34But what I tell you is this. Do not use any name to make a promise stronger. Do not use the words “by heaven” to make a promise stronger. Heaven is the place where God rules. Do not use the words “by the earth” to make a promise stronger. The earth is the place where God rests his feet.

35Do not use the words “by Jerusalem” to make a promise stronger. Jerusalem is God's city. He is the great King who rules from there.

36Do not use the words “by my head” to make a promise. You cannot make the colour of even one of your hairs black or white.

37Instead, when you make a promise, you should say only “Yes, I will do it.” Or you should say only “No, I will not do it.” If you say anything more than this, what you say is bad. It comes from Satan.’