Leviticus 19:12

Ye shall not swear by my name falsely: this is here added, to show how one sin draws on another, and that when men will lie for their own advantage, they will easily be induced to perjury. Neither shalt thou profane the name of thy God, by any unholy use of it. So it is an additional precept, thou shalt not abuse my holy name by swearing either falsely or rashly. Or this may be a reason of the former prohibition, because in so doing thou wilt profane the name of thy God.