The design of these verses is,

I.To arm the people of God against idolatry and all false worship, by showing what sort of gods they were that the heathen worshipped, as we had it before, Psa 115:4, etc. 1. They were gods of their own making; being so, they could have no power but what their makers gave them, and then what power could their makers receive from them? The images were the work of men's hands, and the deities that were supposed to inform them were as much the creatures of men's fancy and imagination. 2. They had the shape of animals, but could not perform the least act, no, not of the animal life. They could neither see, nor hear, nor speak, nor so much as breathe; and therefore to make them with eyes, and ears, and mouths, and nostrils, was such a jest that one would wonder how reasonable creatures could suffer themselves to be so imposed upon as to expect any good from such mock-deities. 3. Their worshippers were therefore as stupid and senseless as they were, both those that made them to be worshipped and those that trusted in them when they were made, Psa 135:18. The worshipping of such gods as were the objects of sense, and senseless, made the worshippers sensual and senseless. Let our worshipping a God that is a Spirit make us spiritual and wise.

II.To stir up the people of God to true devotion in the worship of the true God, Psa 135:19-21. The more deplorable the condition of the Gentile nations that worship idols is the more are we bound to thank God that we know better. Therefore, 1. Let us set ourselves about the acts of devotion, and employ ourselves in them: Bless the Lord, and again and again, bless the Lord. In the parallel place (Psa 115:9-11), by way of inference from the impotency of idols, the duty thus pressed upon us is to trust in the Lord; here to bless him; by putting our trust in God we give glory to him, and those that depend upon God shall not want matter of thanksgiving to him. All persons that knew God are here called to praise him - the house of Israel (the nation in general), the house of Aaron and the house of Levi (the Lord's ministers that attended in his sanctuary), and all others that feared the Lord, though they were not of the house of Israel. 2. Let God have the glory of all: Blessed be the Lord. The tribute of praise arises out of Zion. All God's works do praise him, but his saints bless him; and they need not go far to pay their tribute, for he dwells in Jerusalem, in his church, which they are members of, so that he is always nigh unto them to receive their homage. The condescensions of his grace, in dwelling with men upon the earth, call for our grateful and thankful returns, and our repeated Hallelujahs.

Bless the Lord, O house of Israel,.... Who are chosen by the Lord to be a special people to him above all others; redeemed from Egyptian bondage; through a variety of surprising providences brought into and settled in the land of Canaan; distinguished by various blessings, favoured with the word, worship, and ordinances of God, and not left to worship idols of gold and silver, as other nations; and therefore had great reason to bless the Lord: as also the spiritual Israel, or the household of God and of faith, the family of Christ; and that because they are of his family, because of the love of God to them, his choice of them, his covenant with them, their redemption by Christ, their effectual calling; or for being made Israelites indeed, and the provisions made for them in the house of God for their spiritual welfare;

bless the Lord, O house of Aaron: who were separated from their brethren to minister in the priest's office; to offer gifts and sacrifices for the people, and to bless them, Exo 28:1; which was a very sacred and honourable employment, and they were under obligation to bless the Lord, who had called them to it, and put this honour on them; as are the ministers of the Gospel, who have received gifts from Christ; whom he has counted faithful, and put into the ministry; made stewards of the mysteries of his grace, and ambassadors in his stead; and especially if made useful for edification and conversion: and indeed all the Lord's people, who are all made priests unto God, and have nearness unto him, liberty and boldness to enter into the holiest of all, as Aaron once a year into the most holy place; and who have better sacrifices to offer than he, the living sacrifices of their own bodies and souls, and not slain beasts; spiritual sacrifices of prayer and praise; and, above all, the sweet smelling sacrifice of Christ they bring in the arms of faith, and so enter into the courts of God.