"For there is not a just man upon earth, that doeth good, and sinneth not." (Ecclesiastes 7:20)
When the self-righteous men in the crowd surrounding the woman caught in the act of adultery were about to stone the woman (apparently indifferent to the man with whom she had been caught!), the Lord Jesus turned them all away with His suggestion that the privilege of casting the first stone should go to one who was without sin of his own (John 8:7). They realized that He knew the condition of their sinful hearts, and "being convicted by their own conscience, went out one by one" (John 8:9).
This incident is a perpetual reminder that "the Father . . . hath committed all judgment unto the Son" (John 5:22), not to any one of us. We are not qualified to judge others, since we ourselves are also sinners--saved sinners, perhaps, but sinners.
One of the most certain doctrines of Scripture is the universality of sin in human experience. "There is none that doeth good, no, not one," the Scripture says (Romans 3:12). "For all have sinned, and come short of the glory of God" (Romans 3:23). "Death passed upon all men, for that all have sinned" (Romans 5:12). "The Scripture hath concluded all under sin" (Galatians 3:22). "Therefore to him that knoweth to do good, and doeth it not, to him it is sin" (James 4:17). "For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all" (James 2:10). These and many other Scriptures tell us clearly that, while we urgently need to judge sin in ourselves, we are not qualified to condemn others, at least not on a personal level.
Only the Lord Jesus Christ, being Himself sinless (1 Peter 2:22), can judge a sinner. Thus it is only He who could be made sin for us (2 Corinthians 5:21) and thereby forgive sins and bring salvation. HMM