Is Breaking a Promise a Sin?

“I couldn’t come yesterday; sorry to make you wait.” How many times have we either heard or said this sentence or something to the same effect?  This may seem like something trivial to most of us and we don’t give it even a second thought.  However, in reality, this is a serious matter that we should be concerned with. “O you who believe! Fulfill your promises.” [Al-Ma’idah: 1] Misconception about