After question 44 answered for us, What is baptism?, question 45 takes up another essential issue:

Now, again, we believe that baptism is a sign of Christ’s death and resurrection, His work on our behalf. So when we affirm that baptism does not wash away sin itself, this should not be taken as diminishing baptism in any way. Baptism remains an essential part of the Christian faith. In fact, Peter’s statement in his epistle that “baptism saves you” is true. Baptism is part of our walking in obedience to Christ. It is essential.

We can put it like this: baptism is not essential for salvation, but baptism is essential for the Christian life. For a believer who comes to Christ and then dies immediately, we need not fear for their salvation. Baptism is not the mechanism by which sins are washed away. A person who trusts in Christ yet dies before baptism is not judged because the ordinance was withheld from them. But for the ordinary Christian who continues living and following Christ, baptism is necessary. It is essential because Christ commanded it, and His people obey His commands (John 14:15).

In our earlier discussion of question 43, we said that baptism points us to our justification—our once-for-all salvation in Christ—while the Lord’s Supper points us more directly to sanctification. That is true. But it is also important to say this clearly: baptism is not part of our justification. Baptism signifies justification, but the act of baptism itself belongs to the early stages of sanctification. Baptism looks back to what Christ has already accomplished in justification, even as it marks the believer’s entrance into a life of obedience and renewal.

The waters of baptism do not cleanse from sin. Only the blood of Christ and the renewing work of the Holy Spirit can do that. As Hebrews reminds us, “without the shedding of blood there is no forgiveness of sins.” The wages of sin is death; we have all sinned; therefore every sin must be judged. God does not overlook sin. It must be paid for. And so every human being faces one of two possibilities: either we bear the penalty for our own sins on the day of judgment, or Christ bears it for us, which He has already done on the cross.

His shed blood is the sign that the punishment of our sin has been paid. And the Holy Spirit is the one who enters the heart, applies the finished work of Christ, and dwells within us. Ephesians 1 calls the Spirit the “guarantee” or “down payment” of our inheritance, God’s assurance that our salvation is full and complete, and that we will one day see its final fulfillment.

This is what cleanses us from sin.

The catechism pairs this question with a wonderfully fitting verse, Luke 3:16:

That text makes the point clear: water baptism is not the final reality. Christ brings something greater, the spiritual work promised through Ezekiel and Jeremiah, where God gives His people new hearts, new spirits, and writes His law upon their hearts.

So let us look at baptism with love and respect for what it is, not for what it is not. Baptism is essential for the Christian life. It is not essential for salvation.