Why Christ Gathers the Worst of Men

I have read a lot of John Calvin. I find him to be the most consistently edifying author I spend time with. However, even Calvin can at times surprise with his depth of theological understanding, his clarity in writing and his passion for Christ.  As I studied Matthew 9:7-13, the call of Matthew, I came across a wonderful section in Calvin's commentary on what Christ came to do. Calvin was noting that Matthew was a very wicked man when Christ called him. He also noted that it surprised the Pharisees that Jesus called Matthew.  Then Calvin explains why Christ calling the most wicked of men should not shock us.

"He [Christ] came to quicken the dead, justify the guilty and condemned, to wash those who were polluted and full of uncleanness, to rescue the lost from hell, to clothe with his glory those who were covered with shame, to renew to a blessed immortality those who were debased with disgusting vices. If we consider that this was his office and the end of his coming-if we remember that this was the reason why he took upon him our flesh, why he shed his blood, why he offered the sacrifice of his death, why he descended even to hell, we will never think it strange that he should gather to salvation those who have been the worst of men, and who have been covered with a mass of crimes." (Commentary on Harmony of the Gospels, p. 402)