“You have also heard that our ancestors were told, ‘You must not break your vows; you must carry out the vows you make to the Lord.’ But I say, do not make any vows! Do not say, ‘By heaven!’ because heaven is God’s throne. Just say a simple, ‘Yes, I will,’ or ‘No, I won’t.’ Anything beyond this is from the evil one.” Matthew 5:33, 35, 37
The Pharisees had an elaborate system of oath taking, which was the basis of actual lying. For example, one might swear that he had told the truth according to the dome of the Temple, while another might swear by the gold on the dome of the temple. In other words, there were stages of truth and thus also of falsehood within the system of taking oaths. In our time, this custom is found in phrases such as; “I swear by God”, “cross my heart and hope to die”, or “on my mother’s grave”. Jesus was saying that oath-taking was unnecessary if one was normally in the habit of telling the truth. We ought not to have to call on anyone to back up our word; our word ought to be sufficient; whether people believe us or not is a matter of indifference.
Until Jesus comes into our lives, we are not sincere, not even honest, but when His life is our life, He makes us honest with ourselves and with others. Our conversation should spring from such a basis of His Spirit in us that everyone who listens is built up by what we say. Speak simply and truly, realizing that truth in human beings is the same truth in God. To call God as a witness to back up what you say is nearly always a sign that what you are saying is not true.
Let people do what they like with your truth, but never explain it. Jesus never explained anything; we are always explaining, and we get into tangles by not leaving things alone. We need to pray Saint Augustine’s prayer, “O Lord, deliver me from this lust of always vindicating myself.”
When you say yes, let it be yes. When you say no, let it be no. When we have to use an oath we are admitting that our normal conversation cannot be trusted, or we are lowering ourself to the level of the world.
“You used to do these things when your life was still part of this world. But now is the time to get rid of anger, rage, malicious behavior, slander, and dirty language. Don’t lie to each other, for you have stripped off your old sinful nature and all its wicked deeds.” (Colossians 3:7-9)