It is quite remarkable that “the thief on the cross” is still presented by people today as purported Biblical evidence that one does not really have to be baptized to be saved. Denominations have been making this argument for years, but the truth is that the Bible does not teach or support such a conclusion.
In reality, the thief on the cross was saved in the same way that the paralytic man was saved in Mark 2:5. Jesus said to the paralytic, “Son, your sins are forgiven you.” Yet, in this story, this man was saved, not by his faith, but “when Jesus saw their faith,” the faith of the men who carried him to Jesus. Yes, the paralytic was saved without being baptized. In fact, as far as we know from the Biblical account, the paralytic was saved without believing in Jesus, without loving the Lord, without repenting of his sins and without confessing his faith. Yet, no one would suggest someone could be saved today without doing these things. So, how could that man be saved from his sins in a way different than man today?
First, the student of the Bible will recognize that the thief and the paralytic lived under the Old Covenant, which obviously did not necessitate baptism for salvation. (Read also about Jesus forgiving the sinful woman in Luke 7:48-50 and Zacchaeus in Luke 19:9-10 under similar circumstances.) Just as Moses and David did not have to be baptized, the thief did not have to be baptized, as the law of Christ (i.e., His last will and testament) was not in effect until after His death (Heb. 9:15-17). One is subject to the law under which he lives. Today, we are all subject to the law of Christ in the New Testament. To take a case of salvation before the cross and ignore the thousands of cases of conversion in the book of Acts is not handling aright the Word of God.
Second, the student of the Bible needs to read what Jesus said when He healed the paralytic (without any faith or obedience from the paralytic). “The Son of Man has power on earth to forgive sins” (Mark 2:10). While on earth, before His testament went into effect, Christ could forgive sin of whomever He desired, independent of baptism on their part. But, once the Savior’s will was probated after His death, the terms of pardon were set out in written record to be kept throughout all generations until He comes again. And, no one has a right to alter His will and promise forgiveness through some other means than that which He commanded.