Psalms 135:1

Here is, 1. The duty we are called to - to praise the Lord, to praise his name; praise him, and again praise him. We must not only thank him for what he has done for us, but praise him for what he is in himself and has done for others; take all occasions to speak well of God and to give his truths and ways a good word. 2. The persons that are called upon to do this - the servants of the Lord, the priests and Levites that stand in his house, and all the devout and pious Israelites that stand in the courts of his house to worship there, Psa 135:2. Those that have most reason to praise God who are admitted to the privileges of his house, and those see most reason who there behold his beauty and taste his bounty; from them it is expected, for to that end they enjoy their places. Who should praise him if they do not? 3. The reasons why we should praise God. (1.) Because he whom we are to praise is good, and goodness is that which every body will speak well of. He is good to all, and we must give him the praise of that. His goodness is his glory, and we must make mention of it to his glory. (2.) Because the work is its own wages: Sing praises to his name, for it is pleasant.

— Matthew Henry's Concise Commentary (public domain)