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 Deuteronomy 6:13.

After laying down the fundamental condition of a proper relation towards God, Moses describes the fear of God, i.e., true reverence of God, in its threefold manifestation, in deed (serving God), in heart (cleaving to Him; cf. Deuteronomy 4:4), and with the mouth (swearing by His name; cf. Deuteronomy 6:13). Such reverence as this Israel owed to its God; for "He is thy praise, and He is thy God" (Deuteronomy 10:21). He has given thee strong inducements to praise. By the great and terrible things which thine eyes have seen, He has manifested Himself as God to thee. "Terrible things" are those acts of divine omnipotence, which fill men with fear and trembling at the majesty of the Almighty (cf. Exodus 15:11). אתּך עשׂה, "done with thee," i.e., shown to thee (את in the sense of practical help).

Thou shalt fear the LORD thy God; him shalt thou serve, and to him shalt thou cleave, and {i} swear by his name.

(i) Read De 6:13.

10:20 To him shalt thou cleave - With firm confidence, true affection, and constant obedience.

Margin fear

See Scofield Note: "Ps 19:9".

10:12-22 We are here taught our duty to God in our principles and our practices. We must fear the Lord our God. We must love him, and delight in communion with him. We must walk in the ways in which he has appointed us to walk. We must serve him with all our heart and soul. What we do in his service we must do cheerfully, and with good will. We must keep his commandments. There is true honour and pleasure in obedience. We must give honour to God; and to him we must cleave, as one we love and delight in, trust in, and from whom we have great expectations. We are here taught our duty to our neighbour. God's common gifts to mankind oblige us to honour all men. And those who have themselves been in distress, and have found mercy with God, should be ready to show kindness to those who are in the like distress. We are here taught our duty to ourselves. Circumcise your hearts. Cast away all corrupt affections and inclinations, which hinder you from fearing and loving God. By nature we do not love God. This is original sin, the source whence our wickedness proceeds; and the carnal mind is enmity against God, for it is not subject to the law of God, neither indeed can be; so then they that are in the flesh cannot please God, Ro 8:5-9. Let us, without delay or reserve, come and cleave to our reconciled God in Jesus Christ, that we may love, serve, and obey him acceptably, and be daily changed into his image, from glory to glory, by the Spirit of the Lord. Consider the greatness and glory of God; and his goodness and grace; these persuade us to our duty. Blessed Spirit! Oh for thy purifying, persevering, and renewing influences, that being called out of the state of strangers, such as our fathers were, we may be found among the number of the children of God, and that our lot may be among the saints.