Jesus teaches that Christians should avoid meaningless or abusive oaths, as truthfulness should come from the sincerity of one's heart rather than any oath. While God instituted oaths and Jesus and Paul took oaths when needed, the focus should be on simply telling the truth in all situations through having a truthful heart, rather than invoking oaths to try to add weight to one's statements. Christians are free to take oaths when properly needed, but the emphasis is on cultivating truthfulness through one's character rather than any verbal formula.