The Rambam in ספר המצוות, elaborates on the obligation for one to be careful to fulfill what comes out of one's mouth. Initially, we take this as referring to various pledges that we might make.
There are times that we make a vow or an oath that we must be certain to fulfill. This is equally true of monetary commitments in the form of charity that we must also be sure not to forget to pay as soon as possible.
The Rambam also speaks of another type of speech. He refers to how careful we must be to keep our word. When we say we are going to do something, we must do it. We must never mislead people.
In a business transaction, we must give the other party the benefit of the doubt if what we said might be misunderstood. It is better to even take a loss of money, rather than have our good name compromised. We should be careful to make ourselves clear so that there not be any misunderstandings. Guarding our mouths poses a much bigger challenge than we might realize. It is a major test of faith.
Yesterday was 34 with ספירת העומר