Charles H. Spurgeon on Psalms 135:5

For I know that the LORD is great, etc. On what a firm foundation does the Psalmist plant his foot —"I know!" One loves to hear men of God speaking in this calm, undoubting, and assured confidence, whether it be of the Lord's goodness or of the Lord's greatness. You may perhaps say, that it required no great stretch of faith or knowledge, or any amount of bravery, to declare that God was great; but I think that not many wise nor mighty had in the Psalmist's days attained unto his knowledge or made his confession, that Jehovah, the God of Israel, was "above all gods." Baal and Chemosh, and Milcom and Dagon, claimed the fealty of the nations round about; and David, in the Court of Achish, would have found his declaration as unwelcome, as it would have been rejected as untrue. Moses once carried a message from Jehovah to the king of Egypt, and his reply was, "Who is the Lord, that I should obey his voice? I know not the Lord; "and even of Jehovah's peculiar treasure, all were not Israel that were of Israel. There is a knowledge that plays round the head, like lightning on a mountain's summit, that leaves no trace behind; and there is a knowledge that, like the fertilizing stream, penetrates into the very recesses of the heart, and issues forth in all the fruits of holiness, of love, and peace, and joy for evermore. —Barton Bouchier.