“And the work of righteousness shall be peace; and the effect of righteousness quietness and assurance forever”
The question one may ask, is what is the work of righteousness? We read in Psalms 24:5, He shall receive the blessing from the LORD, and righteousness from the God of his salvation. There is only one that is righteous and able to transfer this righteousness or goodness to an individual. God in his mercy performs this work of righteous by bringing salvation to His people. So then what is this work of righteousness or goodness then?
Our answer can be found in Titus 3:5 Not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost. The scriptures show us that we are dead in sins and trespasses and that our works cannot save us. This work of righteousness is none other than the atonement of Christ for His Elect. Christ is the one who is carrying out this work of righteousness on behave of His people.
To put in another way, the work of Righteousness is the work of Christ in saving His people, and becoming sin for them, and suffering hell in their place. This is why only God can do this work of righteousness. The Jews in Jesus day asked, what shall we do, that we might work the works of God? (John 6:28) Jesus, replied to them, this is the work of God that ye believe (John 6:29). To believe is a work and it is only by the work of God that we believe and are declared righteous. William Mason said this, “For as there is but one atonement by which guilty sinners are pardoned, so there is but one righteousness, even Christ’s perfect righteousness, by which alone unrighteous sinners are made righteous in God’s sight. He accepts no other. His law is honored by no other! The Scriptures reveal no other. Therefore, we pray that we may be found in Christ, not having our own righteousness.” (Philippians 3:9)