Thou hast with [thine] arm redeemed thy people, the sons of Jacob and Joseph. Selah.
Ver. 15. Thou hast with thine arm redeemed thy people] viz. Out of the bondage of Egypt, that memorable mercy; but nothing to that of ours and theirs from sin's thraldom.
The sons of Jacob and Joseph] Joseph is instanced, quia nobilis inter fratres, vel in malis quae pendit, vel in bonis quae rependit, as Austin hath it (De Doct. Christ. 1. iv. c. 6).