(3) When thou didst terrible things . . .--The latter clause, "thou camest down . . ." is supposed by some critics to be an accidental repetition from Isaiah 64:1. By others it is taken as an intentional repetition, emphasising the previous assertion, after the manner of Hebrew poetry. The latter view seems to have most in its favour.

Verse 3 - When thou didst terrible things (comp. Deuteronomy 10:21; 2 Samuel 7:23; Psalm 49:4; Psalm 106:22). The phrase, as Mr. Cheyne remarks, is a "standing" one for the wonders of the Exodus. Which we looked not for; i.e. which transcended our utmost expectations. Thou earnest down (see Exodus 19:11, 20).

64:1-5 They desire that God would manifest himself to them and for them, so that all may see it. This is applicable to the second coming of Christ, when the Lord himself shall descend from heaven. They plead what God had used to do, and had declared his gracious purpose to do, for his people. They need not fear being disappointed of it, for it is sure; or disappointed in it, for it is sufficient. The happiness of his people is bound up in what God has designed for them, and is preparing for them, and preparing them for; what he has done or will do. Can we believe this, and then think any thing too great to expect from his truth, power, and love? It is spiritual and cannot be comprehended by human understanding. It is ever ready. See what communion there is between a gracious God and a gracious soul. We must make conscience of doing our duty in every thing the Lord our God requires. Thou meetest him; this speaks his freeness and forwardness in doing them good. Though God has been angry with us for our sins, and justly, yet his anger has soon ended; but in his favour is life, which goes on and continues, and on that we depend for our salvation.When thou didst terrible things, which we looked not for, thou camest down,.... Referring to the wonderful things God did in Egypt, at the Red sea, and in the wilderness, and particularly at Mount Sinai, things that were unexpected, and not looked for; then the Lord came down, and made visible displays of his power and presence, especially on Mount Sinai; see Exodus 19:18,

the mountains flowed down at thy presence; not Sinai only, but others also; Kimchi says Seir and Paran; Judges 5:4.