Justification is necessary because of the universality of sin.
- all have sinned and fall short of the glory of God, - Romans 3:23
Therefore everyone needs to have their sin removed. Justification cannot be obtained without the finished work and shed blood of Jesus Christ. Therefore, Jesus died for the sins of humanity.
- For while we were still helpless, at the right time Christ died for the ungodly. […] But God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us. - Romans 5:6, 8
- For I delivered to you as of first importance what I also received, that Christ died for our sins according to the Scriptures, - 1 Corinthians 15:3
Only the shed blood of Jesus can appease the wrath of God and justify the sinner in His sight.
- Much more then, having now been justified by His blood, we shall be saved from the wrath of God through Him. - Romans 5:9
When God removes sin, He removes if as far as the East is from the West and remembers it no more.
- As far as the east is from the west, So far has He removed our transgressions from us. - Psalm 13:12
- I, even I, am the one who wipes out your transgressions for My own sake, And I will not remember your sins. - Isaiah 43:25
That something is removed necessitates that it be replaced with something else. Thus, when God removes sin from a person’s life, He replaces it the righteousness of Christ.
- He made Him who knew no sin to be sin on our behalf, so that we might become the righteousness of God in Him. - 2 Corinthians 5:21