Deuteronomy 10:20 in the World English Bible
You shall fear the LORD your God. You shall serve him. You shall cling to him, and you shall swear by his name.
Context
19 Love ye therefore the stranger: for ye were strangers in the land of Egypt.
20 Thou shalt fear the LORD thy God; him shalt thou serve, and to him shalt thou cleave, and swear by his name.
21 He is thy praise, and he is thy God, that hath done for thee these great and terrible things, which thine eyes have seen.