As expressed in the old gospel hymn, the "blessed assurance, Jesus is mine" is a "foretaste of glory divine." According to our text, this "assurance for ever," together with true peace of soul and quietness of spirit, are products of the "work of righteousness."
The New Testament exposition of genuine righteousness makes it clear that we who have received Christ's work of righteousness by faith have been "made the righteousness of God in him" (2 Corinthians 5:21). "To him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness" (Romans 4:5).
Thus, salvation is the priceless possession of those to whom Christ's work of righteousness has been imputed, through faith. On the other hand, the assurance of salvation, accompanied by quietness and peace of heart, is "experienced" only by saved believers who practice the work of righteousness in their daily walk with the Lord. If we truly have salvation, then we ought to manifest the "things that accompany salvation. . . . For God is not unrighteous to forget your work and labour of love, which ye have showed toward his name. . . . And we desire that every one of you do show the same diligence to the full assurance of hope unto the end" (Hebrews 6:9-11).
We can, indeed, know that we are saved simply through faith in His work and His Word (e.g., 1 John 5:13). Nevertheless, to know that one's faith itself is genuine, God has given us this test of faith. "And hereby we do know that we know him, if we keep his commandments" (1 John 2:3).
This is surely blessed assurance of salvation and a foretaste of glory divine! HMM