O give thanks unto the Lord - The psalm closes, as it began, with an exhortation to praise God. In the beginning of the psalm, it was a general exhortation; here it is an exhortation founded on the course of thought in the psalm, or as a proper conclusion from what had been referred to in the psalm. Evidence had been given that the Lord was good; on the ground of that, all people are exhorted to give him thanks.

O give thanks unto the Lord - This is the general doxology or chorus. All join in thanksgiving, and they end as they began: "His mercy endureth for ever." It began at the creation of man; it will continue till the earth is burnt up.

O give thanks unto the Lord, for he is good,.... And thus the psalm ends as it began; there having been given many instances of the divine goodness, in hearing and delivering the psalmist when in distress; saving him from his enemies, when compassed about with them; sparing his life, when in great danger; and especially in making the stone rejected by the builders the head of the corner;
for his mercy endureth for ever; the above instances are proofs of it; and still it continues, and will for evermore. Here ends the great "Hallel", or hymn, sung at the passover and other festivals.