Verse 15. - Thou hast with thine arm (i.e. with thy mighty strength) redeemed thy people. The deliverance from Egypt is constantly called a "redemption" (Exodus 6:6; Exodus 15:13; Deuteronomy 7:8; Deuteronomy 9:26, etc.; 2 Samuel 7:23; 1 Chronicles 17:21, etc.). It is brought forward here "as the greatest and most wonderful of all the works of God, and hence as containing the strongest pledge of future deliverance" (Hengstenberg). The sons of Jacob and Joseph. A new designation of the people of Israel, and one which elsewhere occurs only in Obadiah 1:18. Professor Cheyne suggests that it is a geographical division - by Jacob southern Israel, and by Joseph northern Israel, being intended (comp. Hosea 12:2; Amos 5:6, 15; Amos 6:6).

77:11-20 The remembrance of the works of God, will be a powerful remedy against distrust of his promise and goodness; for he is God, and changes not. God's way is in the sanctuary. We are sure that God is holy in all his works. God's ways are like the deep waters, which cannot be fathomed; like the way of a ship, which cannot be tracked. God brought Israel out of Egypt. This was typical of the great redemption to be wrought out in the fulness of time, both by price and power. If we have harboured doubtful thoughts, we should, without delay, turn our minds to meditate on that God, who spared not his own Son, but delivered him up for us all, that with him, he might freely give us all things.Thou hast with thine arm redeemed thy people,.... The people of Israel out of Egypt, which was typical of the redemption of the Lord's people by Christ, the arm and power of God:

the sons of Jacob and Joseph. Joseph is particularly mentioned for honour's sake, and because he was the means of supporting Jacob and his family in Egypt; and had special faith in their deliverance from thence; the Targum is,

"the sons whom Jacob begot, and Joseph nourished.''

Selah. See Gill on Psalm 3:2.