Psalm 135 has no title. It is a mosaic of praise that echoes other Scriptures, especially Psalm 115 and Psalm 136. It calls the servants of Yahweh who stand in his house to praise him, because Yahweh is good and Yah has chosen Jacob for himself, Israel for his own possession. Praise grows from both God's goodness and his covenant love.
The center is a confession: For I know that Yahweh is great, that our Lord is above all gods. God's greatness shows in creation, as he sends clouds, lightning, rain, and wind from his treasuries. It also shows in history. He sent signs and wonders into Egypt, defeated kings like Sihon and Og, and gave their land as a heritage to Israel. Your name, Yahweh, endures forever.
The psalm repeats Psalm 115's mockery of idols: they have mouths but can't speak, eyes but can't see, ears but can't hear. Those who make them will be like them, yes, everyone who trusts in them. The psalm closes by summoning Israel, the priests of Aaron, the Levites, and all who fear Yahweh to bless him from Zion. In the New Testament, Paul says believers turned to God from idols, to serve a living and true God (1 Thessalonians 1:9).