We have here all the nations called in to the blessing and praise of Israel's deliverance. It is still the mercy and truth of Jehovah. Jerusalem having now been made a center, they are called around. The possession of blessing in mercy begets the spirit of blessing; though once forbidding to speak to the Gentiles that they might be saved, because they rejected mercy, filling up their sins, for wrath was come upon them to the end (eis telos)—now, they had tasted mercy, and they can say to the nations, " Praise the Lord, for he is merciful to us."
Here, note too, the greatness of the mercy is felt and put first, for so Israel comes in—brought in under mercy; and then the truth, they being morally restored, is found to have endured and been forever. They could not find it under their lie, yet their lie had abounded to the enduring glory of His truth—under mercy, they had come into this. How deep is the wisdom of God!
This Lord Jehovah, the nations, all the nations are to praise, for this Psalm is the summons by the restored Jews (Israel) as thus under blessing, to the nations to bless Jehovah thus known i.e., upon the ground of the blessing to them, what He had done for them. The summons of Israel restored, for then can they say (so we, in the Gospel of God the Father by Jesus) " for his kindness " (still, observe, putting mercy first) " was strong" or "prevailed," and the truth of Jehovah "forever." This last word is familiar to any reader in the Psalms. Hallelujah! Their knowledge of Jehovah in their own deliverance enables them to speak of Him to others, and call them in in blessing—so of us as to the Gospel.