Psalms 149:1

We have here, I. The calls given to God's Israel to praise. All his works were, in the foregoing psalm, excited to praise him; but here his saints in a particular manner are required to bless him. Observe then, 1. Who are called upon to praise God. Israel in general, the body of the church (Psa 149:2), the children of Zion particularly, the inhabitants of that holy hill, who are nearer to God than other Israelites; those that have the word and ordinances of God near to them, that are not required to travel far to them, are justly expected to do more in praising God than others. All true Christians may call themselves the children of Zion, for in faith and hope we have come unto Mount Zion, Heb 12:22. The saints must praise God, saints in profession, saints in power, for this is the intention of their sanctification; they are devoted to the glory of God, and renewed by the grace of God, that they may be unto him for a name and a praise. 2. What must be the principle of this praise, and that is holy joy in God: Let Israel rejoice, and the children of Zion be joyful, and the saints be joyful in glory. Our praises of God should flow from a heart filled with delight and triumph in God's attributes, and our relation to him.

— Matthew Henry's Concise Commentary (public domain)