Thou shalt fear the Lord thy God,.... Which includes the whole worship of him, external and internal: him shalt thou serve; heartily and sincerely, according to his revealed will, and him only: and to him shall thou cleave; and not turn aside to follow other gods, and worship them: and swear by his name; and his only, whenever it is necessary to take an oath, which should not be done rashly or on trivial accounts; and never by any creature, but by the living God; see Deu 6:13.