Matthew 5:34, 37
But I say to you, “Make no oath at all… but let your “Yes” be “Yes” and let your “No” be “No;” and anything beyond these is of evil.
Promises wouldn’t be necessary if your character was one that could be inherently trusted. There would be no need for the emphatic “I swear!” or the hesitant “Pinky swear?” Communication would be much easier if you only meant “Yes” when you actually said “Yes.” Trust would be assumed rather than earned.
But you don’t always mean what you say. That’s why the Lord commands you to “Make no oath at all.” What type of witness are you leaving when you have to swear by a higher power or “over your dead grandmother’s grave” to assure someone that you’re telling the truth?
I know, this whole concept sounds a little overzealous. Does anybody honestly make oaths on a daily basis? Do you think that promising somebody something is really that wrong? What about swearing you won’t do something ever again? Chances are you’ve even heard your pastor or parents talk like this… everyone does, right? Does it matter who does it? Jesus commanded us not to.
You can stop to think about it for a while if you want to. The truth is simple: It doesn’t matter what your conclusion is… Jesus has spoken and His command is clear: “Let your Yes’ be Yes,’ and your No’ be No!’