(18) Now also when.--Literally, yea, even to old age and grey hairs. Psalm 129:1 shows that this may be a national as well as an individual prayer.

Thy strength.--Literally, thine arm, the symbol of power. (Comp. Isaiah 52:10; Isaiah 53:1, &c)

Unto this generation.--Literally, to a generation, explained by the next clause to mean, to the coming generation.

Verse 18. - Now also when! am old and greyheaded, O God, forsake me not. Surely, then, thou wilt not forsake me when my youth has fled, and my time of weakness and decay has arrived, so that I need thee all the more. At the time of Adonijah's rebellion, David was "old and stricken in years" (1 Kings 1:1) - nearly, if not quite, seventy years of age (2 Samuel 5:4). Until I have showed thy strength (literally, thine own) unto this generation, and thy power to every one that is to come. The psalmist calls on God to sustain him in his old age, not for his own sake, but that he may impress on the rising generation God's might and marvellous acts.

71:14-24 The psalmist declares that the righteousness of Christ, and the great salvation obtained thereby, shall be the chosen subject of his discourse. Not on a sabbath only, but on every day of the week, of the year, of his life. Not merely at stated returns of solemn devotion, but on every occasion, all the day long. Why will he always dwell on this? Because he knew not the numbers thereof. It is impossible to measure the value or the fulness of these blessings. The righteousness is unspeakable, the salvation everlasting. God will not cast off his grey-headed servants when no longer capable of labouring as they have done. The Lord often strengthens his people in their souls, when nature is sinking into decay. And it is a debt which the old disciples of Christ owe to succeeding generations, to leave behind them a solemn testimony to the advantage of religion, and the truth of God's promises; and especially to the everlasting righteousness of the Redeemer. Assured of deliverance and victory, let us spend our days, while waiting the approach of death, in praising the Holy One of Israel with all our powers. And while speaking of his righteousness, and singing his praises, we shall rise above fears and infirmities, and have earnests of the joys of heaven. The work of redemption ought, above all God's works, to be spoken of by us in our praises. The Lamb that was slain, and has redeemed us to God, is worthy of all blessing and praise.Now also, when I am old and grayheaded, O God, forsake me not,.... A repetition of his request, Psalm 71:9; with a reason annexed to it, suggested in the following words:

until I have showed thy strength unto this generation; or, "thine arm" (e); which sometimes the Messiah, Isaiah 53:1; who is the power of by whom he made the worlds, and in whom all things consist; and who has wrought out the salvation people; and is the arm on which they lean, and they are upheld. And the psalmist may be thought to desire that he might be continued a little longer, and be favoured with the presence of God, and the influences of his Spirit and grace; that he might show forth in prophecy, both by word and writing, to the men of the then present age, more things concerning the person, office, and grace of Christ; his sufferings, death, resurrection from the dead, and session at the right hand of God; things which are spoken of in the book of Psalms. Sometimes the arm of the Lord denotes his power and strength, Psalm 44:3; and so it may be taken here; and the next clause seems to be an explanation of it:

and thy power; or "even thy power",

to everyone that is to come; that is, to come into the world, that is to be born into it; namely, the power of God, not only in creating all things out of nothing, and supporting what is made; but in the redemption of men, in the conversion of sinners, and in the preservation of the saints, and in enabling them to hold on and out unto the end: and which is shown forth by the psalmist in what he has committed to writing; and which continue, and will continue, to the end of the world, for the instruction of those that come into it; see Psalm 22:31.

(e) "brachium tuum", V. L. Pagninus, Montanus, Tigurine version, Junius & Tremellius, Piscator, &c.