(18) Knoweth.--See Psalm 1:6, Note.

Verse 18. - The Lord knoweth the days of the upright; literally, of the perfect - those who yield him a complete obedience. God takes loving note of their days, knows their number, and the events which each day will bring. He will cause all things to "work together for their good." And their inheritance shall be for ever (comp. vers. 27, 29, and 37; which all, like this verse, point, albeit vaguely, to a future life). The mere continuance of a man's posterity in a prosperous condition cannot exhaust the meaning of such phrases as, "Their inheritance shall be for ever;" "Dwell for evermore;" "The righteous shall inherit the land, and dwell therein for ever." If David himself meant no more than this, yet the Holy Spirit which inspired him may have meant more. At any rate, to the Christian the words will always bring up the thought of that "inheritance incorruptible, and undefiled, and that fadeth not away, which is reserved for us in heaven" (1 Peter 1:4).

37:7-20 Let us be satisfied that God will make all to work for good to us. Let us not discompose ourselves at what we see in this world. A fretful, discontented spirit is open to many temptations. For, in all respects, the little which is allotted to the righteous, is more comfortable and more profitable than the ill-gotten and abused riches of ungodly men. It comes from a hand of special love. God provides plentifully and well, not only for his working servants, but for his waiting servants. They have that which is better than wealth, peace of mind, peace with God, and then peace in God; that peace which the world cannot give, and which the world cannot have. God knows the believer's days. Not one day's work shall go unrewarded. Their time on earth is reckoned by days, which will soon be numbered; but heavenly happiness shall be for ever. This will be a real support to believers in evil times. Those that rest on the Rock of ages, have no reason to envy the wicked the support of their broken reeds.The Lord knoweth the days of the upright,.... Not only how long they shall live, and so fill up their days, the number of them, as Aben Ezra interprets it; but the nature of their days, whether prosperous or adverse; and causes both to work together for their good; and he knows the work of their days, as Jarchi explains it, the actions done by them in faith and love, and to his honour and glory, and which he approves and accepts of in Christ; see Psalm 1:6;

and their inheritance shall be for ever; in heaven, which is an eternal and never fading one, Hebrews 9:15; and therefore they ought not to fret and be envious.