"For He [God] made Him [Christ] who knew no sin to be sin for us, that we might become the righteousness of God in Him."
Whereas the sins of true churchmen are imputed to Christ, His righteousness is imputed to them. This is the "Great Exchange." Without this amazing, and incredibly gracious arrangement, there would be no provision for the application of the forgiveness of sins, and no one would ever be saved.
Christ bore the sins of the elect on the cross. The redeemed souls are the ones--more than anyone else--who really put the Messiah on the cruel tree. Let us be humbled by this, and love Christ all the more, by grace through faith.
[Puritan quote of the day: "The joy of the Lord is not only the strength, but also the beauty and glory of Christians, (Neh. 8:10)."
--Thomas Brooks, in "Heaven on Earth"]