Jesus taught that people should not add anything to make their words more credible when they promise to do something.

Matthew 5:33-37

33 “You have also heard your religious teachers say that it was written {that Moses wrote} to your ancestors, ‘Make sure that you do what you promised the Lord that you would do!’ [DOU] 34 But now listen to what I say to you: Never promise to do anything and then ask a superior being to affirm that what you are saying will happen. For example, do not promise that you will give something and then ask spiritual beings in heaven [MTY] to affirm that you will do it, because heaven is where God sits on his throne [MTY] to rule over people. 35 Also, do not promise that you will give something and then ask spiritual beings on earth [MTY] to affirm that you will do it, because the earth is where God rests his feet [MET]. Also, do not promise that you will do something and ask religious authorities in Jerusalem to affirm that you will do it, because Jerusalem is the city where God, the great King rules.

36 Also, do not promise that you will do something and then say that your head should be cut off {someone should cut off your head} if you do not do it. You are not even able to change the color of the hair of your head by making one black hair white or one white hair black. 37 If you talk about doing something, just say ‘Yes, I will do it,’ or ‘No, I will not do it.’ If you say anything more than that, it is from Satan, the Evil One.”