13:1-5 Moses had cautioned against the peril that might arise from the Canaanites. Here he cautions against the rise of idolatry among themselves. It is needful for us to be well acquainted with the truths and precepts of the Bible; for we may expect to be proved by temptations of evil under the appearance of good, of error in the guise of truth; nor can any thing rightly oppose such temptations, but the plain, express testimony of God's word to the contrary. And it would be a proof of sincere affection for God, that, notwithstanding specious pretences, they should not be wrought upon the forsake God, and follow other gods to serve them.Ye shall walk after the Lord your God,.... As he has directed, according to the laws and rules which he has given, both with respect to their moral and civil conduct, and their religious worship of him; and so the Targum of Jonathan,"ye shall walk after the worship of the Lord your God:"

and fear him, and keep his commandments; fear to offend him, and so keep his commandments; or keep his commandments from or through fear; not a servile but a filial one, a reverential affection for him; this is the whole duty of man, Ecclesiastes 12:13,

and obey his voice; in his word, or by his prophets and ministers: it may very well be understood of the voice of Christ, the Angel that went before them, whose voice they were continually to hearken to and obey, Exodus 23:21.

and you shall serve him, and cleave unto him; it may respect all religious worship, both private and public; the Targum of Jonathan restrains it to prayer, but it not only includes that, but all other acts of piety and devotion, and which are to be constantly performed and not departed from; for so to do is to cleave to the Lord as a man to his wife, or a woman to her husband, in which conjugal relation God and his people Israel were, he was an husband unto them, and to do otherwise is to go a whoring from him after other gods.