The LORD builds up Jerusalem; He gathers the exiles of Israel.
God stirs us to praise Him for two reasons: His power and wisdom shown in governing all creation, and His special mercy to His chosen Church, restoring it when it falls, gathering it when scattered. The Psalm likely arose after Jerusalem's rebuilding, when the people saw God's hand return them from captivity.
AI summary
Commenting on Psalm 147:1-20
The Lord doth build up Jerusalem. God appears both ill the material and spiritual world as a Builder and Maker, and therein he is to be praised. His grace, wisdom, and power are all seen in the formation and establishment of the chosen seat of his worship; once a city with material walls, but now a church composed of spiritual stones.
Here, I. The duty of praise is recommended to us. It is not without reason that we are thus called to it again and again: Praise you the Lord (Psa 147:1), and again (Psa 147:7), Sing unto the Lord with thanksgiving, sing praise upon the harp to our God (let all our praises be directed to him and centre in him), for it is good...
Commenting on Psalm 147:1-11