That I may show forth all thy praise - That I may praise time in the land of the living; that I may finish the work of praise by rendering to thee all that is due. The idea is, that the dead could not praise God, or that his praise could be uttered only by the living; and he calls on God, therefore, to interpose and save him, that he might yet worship and praise him on the earth. In this sentiment the psalmist utters only what man naturally feels when he looks upon the grave; that it is an end of human plans and pursuits; that it is a land of silence; that the worship of God is not there celebrated. Such language must be retarded as uttered under the impulse of natural feeling, and not as uttered by the deliberate judgment of the mind when calmly contemplating the whole subject. All pious persons baize these feelings at times, and it was proper that these feelings should be expressed in the sacred writings, as illustrating human nature even under the influence of religion. The same sentiment occurs in several places, as is, that he was apparently near to the gates of death, and that the only one who could raise him up was God, and he now invoked His interposition that it might be done. The phrase “gates of death” relates to the prevalent views about the unseen world - the world where the dead abide. That world was represented as beneath; as a dark and gloomy abode; as enclosed Psalm 115:17, “The dead praise not the Lord, neither any that go down into silence.” See the notes at Psalm 6:5. It is not necessary to say that the sacred writers had brighter views at times than these. But who can keep the mind always from desponding when it looks at the grave? Who can always help feeling that it is a place of darkness and gloom?
In the gates of the daughter of Zion - As contradistinguished from the “gates of death.” Gates in ancient cities were places of concourse, where important transactions were performed; and the “gates” of Jerusalem were regarded as attractive and sacred, because it was through them that the people passed on their way to worship God at the tabernacle or in the temple. Hence, it is said, Psalm 87:2, “The Lord loveth the gates of Zion more than all the dwellings of Jacob.” Psalm 100:4, “enter into his gates with thanksgiving.” Compare Psalm 118:19. The phrase, “daughter of Zion,” means Jerusalem. For the reason of this appellation see the notes at Isaiah 1:8. The language used here proves that the psalm was composed after Zion or Jerusalem was made the capital of the kingdom and the seat of public worship, and, therefore, that it cannot refer, as is supposed in the Aramaic Paraphrase, to the death of Goliath.
I will rejoice in thy salvation - In the salvation which thou wilt bestow on me; here particularly, in delivering him from his dangers. The language, however, is general, and may be employed with reference to salvation of any kind.