Today we recall that the Lord has done great things to the Virgin Mary, whom He graciously chose and blessed to be the Mother of our Lord Jesus Christ by the power of the Holy Spirit. Similarly, in holy Baptism, God has done great things to you, graciously choosing and blessing you to be His child by the power of the Holy Spirit working through water and the Word.
Answer: It is not the water indeed that does them, but the Word of God, which is in and with the water, and faith, which trusts this Word of God in the water. For without the Word of God the water is simple water and no Baptism. But with the Word of God it is a Baptism, that is, a gracious water of life and a washing of regeneration in the Holy Spirit. As St. Paul says in Titus chapter three, "He saved us … by the washing of regeneration and renewal of the Holy Spirit, whom He poured out on us richly through Jesus Christ our Savior, so that being justified by His grace we might become heirs according to the hope of eternal life. The saying is trustworthy" [vv. 5-8].
FOURTH What does such baptizing with water signify?
Answer: It signifies that the old Adam in us should, by daily contrition and repentance, be drowned and die with all sins and evil lusts. And also it shows that a new man should daily come forth and arise, who shall live before God in righteousness and purity forever.
Where is this written?
Answer: St. Paul says in Romans chapter 6, "We were buried therefore with Him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life" [v. 4].
Condensed from CONCORDIA: THE LUTHERAN CONFESSIONS, copyright 2005,2006 by Concordia Publishing House. Used by permission. All rights reserved. To purchase a copy of CONCORDIA, call 800-325-3040.
Lord grant you faith in His grace alone for your salvation unto eternal life. Amen