This Psalm declares in such a plain and powerful way all the covenant
promises made with the Lord Jesus Christ that are eternal and certain
(Psa. 89:3,28,34,37). Many commentators of scripture have called this
Psalm, "The glorious covenant Psalm" and truly it is. We read about
covenant mercies, covenant faithfulness of the Surety, the covenant God
Who rules over all and the promise to the covenant seed being
established forever in Christ Jesus (Psa. 89:4,29,36). He is a covenant
God, therefore His covenant people must be blessed (Eph. 1:3). God gives
us this glorious description of His people in verses 15,16,17 of this
Psalm.
1). They know the joyful sound of the gospel. The sheep of Christ know the effectual voice of the Great Shepherd and they delight to follow Him (John 10:27-30). It is the sound of victory over sin through His blood. It is the sound of love, peace and pardon in and through Christ Jesus (Eph. 1:6).
2). They shall walk in the light of His countenance. Their darkened heart has been illuminated through the preaching of the gospel and the quickening of the Holy Spirit to see the beauty, glory and necessity of their great Redeemer and King (2 Cor. 4:6). Christ is our Light (John 9:5).
3). They shall rejoice in His name all the day. Believers have every reason to rejoice in Christ alone and have no confidence in the flesh (Phil. 3:3). They have been redeemed, justified and exalted in His name.
4).They shall be exalted in His righteousness. The perfect righteousness that Jesus Christ worked out for His elect has been freely, eternally and fully imputed to them that believe (Rom. 4:6). Christ Jesus is the Lord our Righteousness (Jer. 23:5; Phil. 3:7-9). From sin and misery to all grace and glory. From the gutter-most sin to the uttermost salvation (Heb. 7:25).20
5). The Lord Jesus Christ is our glory and strength. Without Him we can do nothing and know nothing (Jn. 15:5). Any spiritual strength or spiritual knowledge that we enjoy and experience, must be because of His grace worked within us (Phil. 1:6; 4:13).
6). The Lord is our defense. We are unable to defend ourselves against our spiritual enemies, there are too many of them and they are too powerful for us even to begin to fight. However, our Lord stood face to face with all our enemies and won the glorious victory for us (Psa. 98:1). He defeated sin by making atonement for it (Heb. 9:26). He honored the Law for us (Gal. 3:13). He defeated Satan by crushing his dominion and power (Heb. 2:14). He defeated death by raising Himself from the dead (Rev. 1:18).