With long life will I satisfy him - The margin here, is "length of days;" that is, days lengthened out or multiplied. The meaning is, I will give him length of days as he desires, or until he is satisfied with life; implying
(1) that it is natural to desire long life;
(2) that long life is to be regarded as a blessing (compare Proverbs 3:2, Proverbs 3:16; Exodus 20:12);
(3) that the tendency of religion is to lengthen out life; since virtue, temperance, regular industry, calmness of mind, moderation in all things, freedom from excesses in eating and in drinking - to all of which religion prompts - contribute to health, and to length of days (see Psalm 34:12-14, notes; Psalm 37:9, note; Psalm 55:23, note); and
(4) that a time will come, even under this promised blessing of length of days, when a man will be "satisfied" with living; when he will have no strong desire to live longer; when, under the infirmities of advanced years, and under his lonely feelings from the fact that his early friends have fallen, and under the influence of a bright hope of heaven, he will feel that he has had enough of life here, and that it is better to depart to another world.
And shew him my salvation - In another life, after he shall be "satisfied" with this life. The promise extends beyond the grave: "Godliness is profitable unto all things, having promise of the life that now is, and of that which is to come." See the notes at 1-Timothy 4:8. Thus, religion blesses man in this life, and blesses him forever. In possession of this, it is a great thing to him to live long; and then it is a great thing to die - to go to be forever with God.

With long life - Literally, With length of days will I fill him up.
He shall neither live a useless life, nor die before his time. He shall live happy and die happy.
And show him my salvation - ואראהו בשועתי vearehu bishuathi, "I will make him see (or contemplate) in my salvation." He shall discover infinite lengths, breadths, depths, and heights, in my salvation. He shall feel boundless desires, and shall discover that I have provided boundless gratifications for them. He shall dwell in my glory, and throughout eternity increase in his resemblance to and enjoyment of me. Thus shall it be done to the man whom the Lord delighteth to honor; and he delights to honor that man who places his love on him. In a word, he shall have a long life in this world, and an eternity of blessedness in the world to come.

With (k) long life will I satisfy him, and shew him my salvation.
(k) For he is content with that life that God gives for by death the shortness of this life is recompensed with immortality.

With long life will I satisfy him,.... In this world: the saints live in it as long as they choose to live; and when they come to die, be it when it will, they are, like Abraham, full of years, or satisfied with them; they have had enough of them, and would not live always here; but, with good old Simeon, desire to depart in peace; and in the other world they shall be satisfied with length of days, for ever and ever, even with eternal life; and nothing short of this will satisfy a good man:
and show him my salvation; Jesus Christ, the author of salvation, whom God appointed to do it, and who has finished it; salvation itself, wrought out by him; its fulness and suitableness, and interest in it; and also eternal glory and happiness, the completion and consummation of salvation: the former is shown unto and seen by faith here; the latter will be seen and enjoyed in heaven to all eternity. Aben Ezra and Kimchi refer this salvation to the days of the Messiah.

show him--literally, "make him see" (Psalm 50:23; Luke 2:30).