4 But it may be one says, Christ does indeed baptize, but in spirit, not in body. As if, indeed, it were by the gift of another than He that any is imbued even with the sacrament of corporal and visible baptism. Would you know that it is He that baptizes, not only with the Spirit, but also with water? Hear the apostle: “Even as Christ,” says he, “loved the Church, and gave Himself for it, purifying it with the washing of water by the Word, that He might present to Himself a glorious Church, not having spot, or wrinkle, or any such thing.” Purifying it. How? “With the washing of water by the Word.” What is the baptism of Christ? The washing of water by the Word. Take away the water, it is no baptism; take away the Word, it is no baptism.
Source: Tractates on the Gospel of John (New Advent)