That thou mayest love the Lord - Compare Deuteronomy 6:5. Love stands first as the essential and only source of obedience.

He is thy life - Or, "that" (i. e., "to love the Lord") "is thy life;" i. e., the condition of thy life and of its prolongation in the promised land. Compare Deuteronomy 4:40; Deuteronomy 32:47.

That thou mayest love the Lord - Without love there can be no obedience.

Obey his voice - Without obedience love is fruitless and dead.

And cleave unto him - Without close attachment and perseverance, temporary love, however sincere and fervent - temporary obedience, however disinterested, energetic, and pure while it lasts - will be ultimately ineffectual. He alone who endures to the end, shall be saved. Reader, how do matters stand between God and thy soul? He cannot persevere in the grace of God whose soul is not yet made a partaker of that grace. Many talk strenuously on the impossibility of falling from grace, who have not yet tasted that the Lord is gracious. How absurd to talk and dispute about the infallibility of arriving safely at the end of a way in which a man has never yet taken one hearty step! It is never among those that have the grace of God, but among those that have it not, that we find an overweening confidence.

That thou mayest love the Lord thy God,.... And show it by keeping his commands:

and that thou mayest obey his voice; in his word, and by his prophets:

and that thou mayest cleave unto him; and to his worship, and not follow after and serve other gods:

for he is thy life, and the length of thy days; the God of their lives, and the Father of their mercies; the giver of long life, and all the blessings of it; and which he had promised to those that were obedient, to him, and which they might expect:

that thou mayest dwell in the land which the Lord sware unto thy fathers, to Abraham, to Isaac, and to Jacob, to give them; the land of Canaan, often thus described; this was the grand promise made to obedience to the law, and was typical of eternal life and happiness; which is had, not through man's obedience to the law, but through the obedience and righteousness of Christ.

חיּיך הוּא כּי, for that (namely, to love the Lord) is thy life, that is, the condition of life, and of long life, in the promised land (vid., Deuteronomy 4:40).

That thou mayest love the LORD thy God, and that thou mayest obey his voice, and that thou mayest cleave unto him: for he is thy life, and the length of thy days: that thou mayest dwell in the land which the LORD sware unto thy fathers, to Abraham, to Isaac, and to Jacob, to give them.

30:20 That thou mayest love the Lord thy God - Here he shews them in short, what their duty is; To love God as the Lord, a being most amiable, and as their God, a God in covenant with them: as an evidence of their love, to obey his voice in every thing, and by constancy in this love and obedience, to cleave to him all their days. And what encouragement had they to do this? For he is thy life and the length of thy days - He gives life, preserves life, restores life, and prolongs it, by his power, tho' it be a frail life, and by his presence, tho' it be a forfeited life. He sweetens life by his comforts, and compleats all in life everlasting.

30:15-20 What could be said more moving, and more likely to make deep and lasting impressions? Every man wishes to obtain life and good, and to escape death and evil; he desires happiness, and dreads misery. So great is the compassion of the Lord, that he has favoured men, by his word, with such a knowledge of good and evil as will make them for ever happy, if it be not their own fault. Let us hear the sum of the whole matter. If they and theirs would love God, and serve him, they should live and be happy. If they or theirs should turn from God, desert his service, and worship other gods, that would certainly be their ruin. There never was, since the fall of man, more than one way to heaven; which is marked out in both Testaments, though not with equal clearness. Moses meant that same way of acceptance, which Paul more plainly described; and Paul's words mean the same obedience, on which Moses more fully treated. In both Testaments the good and right way is brought near, and plainly revealed to us.