This is the safest and eternally vital advice you can ever give to a lost sinner. The Holy Scriptures are absolute on this point: human righteousness is entirely bankrupt before the holy God (see Isaiah 64:6), and trying to earn salvation through works, morality, religiousness, or self-effort is the very delusion that keeps a soul bound in Sin.
To advise a sinner to disavow and reject his own righteousness forever, and to trust only in the living Person of Christ Jesus and simply receive His RIGHTEOUSNESS now, is at the very heart of the Gospel. It is the moment when a sinner stops leaning upon the broken reeds of self-justification, abandons every other hope, and rests his entire immortal soul solely upon the FINISHED Atonement of the Lamb of God—the PRECIOUS BLOOD OF GOD—and upon the spotless RIGHTEOUSNESS of the Lord Jesus Christ Himself.
The only thing that can damn a man's soul forever is his own righteousness, and the only thing that can save a man's soul from his sins is Christ's RIGHTEOUSNESS.
Why a Man's Own Righteousness Damns the Soul
The Bankrupt Currency: Human righteousness—whether it comes through moral efforts, religious rituals, good deeds, or self-justification—is described in Scripture as "filthy rags" (Isaiah 64:6). It is utterly incapable of satisfying the righteousness and justice of a holy God.
The Root of Rejection: Trusting in one's own righteousness is ultimately a rejection of THE CROSS. It says, in effect, that Christ's sacrifice of Himself was unnecessary, or that human effort can somehow contribute to satisfying divine justice. Therefore, clinging to self-righteousness means clinging to the very sins of pride and unbelief, leaving the soul exposed to eternal judgment with no Substitute to bear the wrath of God.
The self-righteous man goeth about to establish his own righteousness and hath not submitted himself unto the righteousness of God, which is found only in JESUS CHRIST (Romans 10:3).
Why Christ's Righteousness Saves the Soul
The Perfect Exchange: Salvation is entirely an act of divine grace in which the believer's sin is imputed to Christ, and Christ's spotless, perfect righteousness is imputed to the believer (2 Corinthians 5:21).
The Only Acceptable Covering: Nothing a sinner can do can wash away a single stain of guilt. Only the sinless life, atoning bloody death, and perfect RIGHTEOUSNESS of Jesus Christ Himself can satisfy Divine Justice.
When a soul abandons all self-reliance and receives Christ's Righteousness by faith in His Blood, that soul is clothed in the garment of perfection that Christ Himself finished and that God Himself accepts. In Christ, the believer has an eternal redemption that does not rest upon his own merit, but upon the finished work and perfect Righteousness of the Son of God.
In short, self-righteousness is the trap of human pride that condemns a sinner, while Christ's RIGHTEOUSNESS is the only Ransom provided by God that saves the soul forever.
Therefore, reject every confidence in your own righteousness. Do not attempt to make yourself worthy of Christ. Do not trust your morality, religious works, good deeds, or self-effort to make you acceptable before God. Look away from yourself and look wholly to JESUS CHRIST. Rest your immortal soul upon His finished Atonement, His Precious Blood, and His perfect RIGHTEOUSNESS.
The Lord Jesus Christ alone is all-sufficient. Jesus Christ alone is Righteous. The Lamb of God alone is the Substitute. Christ Jesus alone is the Ransom. And the Crucified Creator alone can save a sinner. Trust only God's Blood and God's Righteousness that is found only in The Precious Lamb of God.