Matthew 5:33-37 Again you have heard that it was said to those of old, ‘You shall not swear falsely, but shall perform to the Lord what you have sworn.’ But I say to you, Do not take an oath at all, either by heaven, for it is the throne of God, or by the earth, for it is his footstool, or by Jerusalem, for it is the city of the great King. And do not take an oath by your head, for you cannot make one hair white or black. Let what you say be simply ‘Yes’ or ‘No’; anything more than this comes from evil.
“His word is his bond” used to be high praise for someone. It meant they were honorable and trustworthy. Jesus is saying that this should be the norm for Christians. Christians should be known for their honesty. When they say something, people should be confident of its accuracy and truthfulness.
The purpose of an oath is to convince the audience that the speaker is going to follow through with what they have said. However, a person with a reputation for honesty does not need to convince people. His or her character is convincing enough. An oath is not effective anyway. If one is a liar, then they can lie in an oath as well as in a statement or promise.
In some ways an oath is like putting collateral down for a loan. The collateral is a guarantee that you will repay the loan. The concept is that if one swears on something greater than themselves (by God, or on a stack of bibles, or on their mother’s grave) that somehow that guarantees the truth or intent of the swearer. However, Jesus points out that if one swears by something greater then they have no power over that thing. Therefore, it offers no guarantee at all.
If we simply live honestly, we will have no need to guarantee our words. That is the way it should be.
Dear God, You are truth. Cause me to be truthful in all things so that people will believe me and trust you.