Deuteronomy 5:11

"You shall not take the name of the LORD your God in vain, for the LORD will not hold him guiltless who takes His name in vain.

Surrounding context

5:10 but showing mercy to thousands, to those who love Me and keep My commandments.

5:11 "You shall not take the name of the LORD your God in vain, for the LORD will not hold him guiltless who takes His name in vain.

5:12 "Observe the Sabbath day, to keep it holy, as the LORD your God commanded you.