The title bears the argument made by most evangelical Protestants; namely, that the sacraments, not to mention the corporal and spiritual works of mercy, are unnecessary unto salvation. The thief, so we’re told, can literally “do nothing” since his hands and feet are nailed down. His mere acknowledgement of Jesus’ kingship wins him a trip that very day to paradise.
Was it, then, faith alone that saved him? I think the quick answer a Catholic would give would be to say that the exception does not disprove the rule. But what is the rule? To help establish the rule, we turn to St. Peter in Acts 2:38 where he tells the crowds, “Repent, and be baptized, every one of you in the name of Jesus Christ so that your sins may be forgiven.” Faith being assumed, repentance (contrition & penance) and baptism seem to be the rule. Did the thief meet these prerequisites?
I would submit to you that the thief fulfilled even the rule on that fateful Good Friday. In addition to his faith, the thief expressed contrition and made reparation (penance). He demonstrated his faith when he acknowledged that Christ has a kingdom to enter (Lk. 23:42). He demonstrated contrition in confession by admitting his own “fear” of God and the “due reward” for his crimes (Lk. 23:40-41). By instructing the ignorant thief and admonishing him, two spiritual works of mercy were accomplished. Christ, then, seeing his faith and contrite heart, allowed the good thief’s suffering to be his penance and his death to be his baptism, for he truly “died with Christ (Romans 6:8).”
“Therefore, we have been buried with him by baptism into death, so that, just as Christ was raised from the dead by the glory of the Father, so we too might walk in newness of life. For if we have been united with him in a death like his, we will certainly be united with him in a resurrection like his.” Romans 6:4-5