To read the texts click on the texts: 2 Cor 5:14-21; Mt 5:33-37
The fourth of the six antitheses is completely a Matthean composition. There is no precedence for the absolute prohibition of oaths in Judaism. Rather, an oath invoked God to guarantee the truth of what was being sworn or promised, or to punish the one taking the oath if he was not faithful to his word.
The Matthean Jesus here rules out oaths completely. He rejects not only false and unnecessary oaths, but also any attempt to bolster one’s statement claim to truth beyond the bare statement of it. It is a demand for truthfulness in everything that one says.