We are here taught, 1. That we owe our lives to God's mercy. David prays, Deal bountifully with me, that I may live. It was God's bounty that gave us life, that gave us this life; and the same bounty that gave it continues it, and gives all the supports and comforts of it; if these be withheld, we die, or, which is equivalent, our lives are embittered and we become weary of them. If God deals in strict justice with us, we die, we perish, we all perish; if these forfeited lives be preserved and prolonged, it is because God deals bountifully with us, according to his mercy, not according to our deserts. The continuance of the most useful life is owing to God's bounty, and on that we must have a continual dependence. 2. That therefore we ought to spend our lives in God's service. Life is therefore a choice mercy, because it is an opportunity of obeying God in this world, where there are so few that do glorify him; and this David had in his eye: "Not that I may live and grow rich, live and be merry, but that I may live and keep thy word, may observe it myself and transmit it to those that shall come after, which the longer I live the better I shall do."

I am a stranger in the earth,.... As all his fathers were, and all the saints are; not to divine and spiritual things; to God, and communion with him; to Christ, and the knowledge of him; to the Spirit, and his operations in their hearts; to their own hearts, and the plague of them; to the Gospel, and its truths; nor to the people of God, and fellowship with them: but to the world, among whom they are, not being known, valued, and respected by them; and they also behaving as strangers to the world, having no fellowship with them in their sinful works; as also not being natives here, but belonging to another city and country, an heavenly one; see Ch1 29:15;

hide not thy commandments from me; the doctrines of the Gospel, the word which God has commanded to a thousand generations; which is pure, and enlightens the eyes, and so needful to strangers in their pilgrimage, Psa 19:8; which God sometimes hides from the wise and prudent, and which the psalmist here deprecates with respect to himself, Mat 11:25. Or the precepts of the world may be meant, which are a light to the feet, and a lamp to the paths, a good direction to travellers and strangers in the way: David, being such an one, prayed that these might not be hid from him, but be showed unto him; that he might know his way, and not go out of it; but walk as a child of light, wisely and circumspectly.