'Swear' in the Bible

You shall fear only the Lord your God; and you shall worship Him and swear by His name.

You shall fear the Lord your God; you shall serve Him and cling to Him, and you shall swear by His name.

Look down from Your holy habitation, from heaven, and bless Your people Israel, and the ground which You have given us, a land flowing with milk and honey, as You swore to our fathers.’