To CALL DOWN A CURSE — to place something under a katathema, an anathema, a thing devoted to destruction. ⚠ It is not swearing in the sense of foul language, which is how KJV's 'began to curse and to swear' (Matthew 26:74) has been read for centuries; it is the formal invocation of a curse on oneself as a guarantee of truthfulness — may this happen to me if I am lying. That is why it is the THIRD step of Peter's denials and not merely a louder version of the first: he denies plainly (v70), then denies under oath (v72), then calls down curses (v74). Denial, perjury, self-imprecation. The word is used only here in the New Testament. → first discussed at Matt 26:74