Question 45: Is baptism with water the washing away of sin itself?
Answer: No, only the blood of Christ and the renewal of the Holy Spirit can cleanse us from sin.
Baptism is an event that marks conversion to Christ. As such, it is closely associated with the spiritual blessings of conversion: the forgiveness of sins, the new birth, and the gift of the Holy Spirit. For example, Peter could say to his hearers on the day of Pentecost, "Repent and be baptized every one of you in the name of Jesus Christ for the forgiveness of your sins, and you will receive the gift of the Holy Spirit" (Acts 2:38). Baptism, as an expression of faith, is here tied to both the forgiveness of sins and the reception of the Spirit. Other examples of such statements include Acts 22:16 and Romans 6:1-4.
Do these kinds of statements in Scripture indicate that baptism itself is the channel of God's forgiving grace and the physical element that brings the Holy Spirit to us? No, the New Testament does not point us toward that conclusion. For example, the book of Acts also includes the story of Philip's proclamation of the gospel to a group of Samaritans (Acts 8). It is interesting to note in that story that, even though all who responded to Philip's preaching were baptized, they did not receive the Spirit until later when Peter and John arrived from Jerusalem to lay hands on them. In addition, it appears that at least one Samaritan who was baptized was not, in fact, a recipient of the Spirit at all, as the account of Simon the magician seems to imply (Acts 8:9-24). In that story, baptism was clearly not the means by which the Spirit was given to the Samaritan believers.
In addition to the Samaritan account, we see in the story of Cornelius the opposite pattern: reception of the Spirit precedes baptism (Acts 10). In fact, it wasn't until Peter preached the gospel and then saw and heard the evidence of the Holy Spirit on Cornelius's household that he drew the conclusion: "Can anyone withhold water for baptizing these people, who have received the Holy Spirit just as we have?" (Acts 10:47). In both the accounts of the Samaritans and of Cornelius, we are able to distinguish between the spiritual blessings of conversion and the physical element that marks conversion, namely, baptism.
But overall, while the Bible can and does at times draw that distinction, it doesn't seem overly concerned to do so in every instance. We should allow ourselves to speak the way Scripture does about baptism, closely associating it with the forgiveness of sins, the new birth, and the reception of the Holy Spirit. We can speak that way without intending or implying that baptism causes any of these things to happen by some power inherent in the act itself. Salvation is by faith alone, not by baptism. But initial faith, in its public form, is baptism.
Suggested passage for personal or family reading: Acts 10. What does this story teach about the preaching of the gospel, faith, receiving the Holy Spirit, and baptism? Are there echoes of the story of Pentecost (Acts 2) in this story about Cornelius?