Baptism signifies that Jesus poured out His blood to secure the forgiveness of all who trust in Him alone. Yet this sacrament signifies and seals other things as well, as question and answer 70 of the Heidelberg Catechism reveal. For those of faith, baptism tangibly reminds us that we have been “washed with Christ’s Spirit,” that “the Holy Spirit has renewed and sanctified us to be members of Christ.”
In baptism, we look back to the work of Christ to secure our forgiveness, but we also see the ongoing work of the Spirit to purify us from all sin. Although the Holy Spirit regenerated the hearts of the old covenant people of God and gave old covenant believers faith in the Lord, the prophets still anticipated a day when the Spirit would be given to Israel in greater measure (Num. 11:29). The prophets looked for a revival, a giving of the Spirit that would put God’s law on the hearts of His people and wash from them any desire to disobey the Lord. Today’s passage is one place where this future hope of the old covenant people is recorded.
As you can see, Ezekiel couples the washing of water with the outpouring of the Spirit. This is a common connection in Scripture, thereby explaining why the Heidelberg Catechism and other creeds and confessions connect the sacrament of water baptism with regeneration and the other acts of the third person of the Trinity (see WLC Q&A 165). Jesus Himself, in John 3:5, speaks of our need to be born of water and the Spirit if we are to see the kingdom of heaven. Although some traditions see a veiled reference to baptism here, the important thing to note is that Jesus connects water and Spirit just like Ezekiel did. Christ’s mentioning of the Holy Spirit and water in the same breath illustrates the Spirit’s work. As John Calvin comments on John 3:5, “It is a frequent and common way of speaking in Scripture, when the Spirit is mentioned, to add the word Water or Fire, expressing his power.”
God the Holy Spirit brings true cleansing and renewal, cleaning us so thoroughly that we regard the filthiness of sin as out of place in our souls, driving us to a life of repentance. Water does a similar thing on an earthly level, refreshing us and establishing a stark contrast between what the water has cleaned and what is dirty. Through the washing of water, Christian baptism illustrates the work of the Spirit.
The sacrament of baptism reminds us that God has cleansed us from all sin and, therefore, that the filthiness of wickedness has no place in our lives. If we have trusted in Jesus Christ by faith alone, then we are in Jesus Christ and must not live as if we are still in Adam. We will fail, and we will still sin until we are glorified. Nevertheless, we are daily to regard sin as out of place in the Christian life, and we are to repent and turn from our evil deeds.