| Barnes' Notes on the Bible Thou hast with thine arm - That is, with strength or power, the arm being a symbol of strength. Exodus 6:6; Exodus 15:16; Psalm 10:15. Redeemed thy people - Thou didst rescue or deliver them from Egyptian bondage. See the notes at Isaiah 43:3. The sons of Jacob and Joseph - The descendants of Jacob and Joseph. Jacob is mentioned because he was the ancestor of the twelve tribes; Joseph, because he was conspicuous or eminent among the sons of Jacob, and particularly because he acted so important a part in the affairs of Egypt, from whose dominion they were redeemed.
Clarke's Commentary on the BibleThe son. of Jacob and Joseph - "The sons which Jacob begat and Joseph nourished." says the Chaldee. The Israelites are properly called the sons of Joseph as well as of Jacob, seeing Ephraim and Manasseh, his sons, were taken into the number of the tribes. All the latter part of this Psalm refers to the deliverance of the Israelites from Egypt; and the psalmist uses this as an argument to excite the expectation of the captives. As God delivered our fathers from Egypt, so we may expect him to deliver us from Chaldea. It required his arm to do the former, and that arm is not shortened that it cannot save.
Gill's Exposition of the Entire BibleThou 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.
Geneva Study BibleThou hast with thine arm redeemed thy people, the sons of Jacob and Joseph. Selah.
Scofield Reference NotesMargin redeemed Heb. "goel," Redemp. (Kinsman type). See Scofield Note: "Isa 59:20".
Jamieson-Fausset-Brown Bible Commentary15. Jacob and Joseph-representing all.
Matthew Henry's Concise Commentary77:11-20 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. | 
