1 Peter 2:4–5 (NKJV)
4 Coming to Him as to a living stone, rejected indeed by men, but chosen by God and precious, 5 you also, as living stones, are being built up a spiritual house, a holy priesthood, to offer up spiritual sacrifices acceptable to God through Jesus Christ.

Peter reminds us that the Church which God is building throughout human history is not essentially a physical structure but an organic community. The foundation of this Church is not concrete but the Apostles and Prophets, Jesus Christ Himself being the chief cornerstone. As members of that Church, those who confess Christ are living stones, living members of the living Temple of God. So it is fitting as we dedicate this physical building to the glory and service of God that we have the privilege of baptizing a stone and bringing him to new life in the Church of God. When John the Baptist preached his baptism of repentance, he declared that God was able to raise up from stones children of Abraham – and so today we have the privilege of baptizing ———, by nature a stone, so that he might become a living stone, united by faith in the working of God to the Church.

By why baptize a baby? Because, as Peter goes on to remind us, we, the Church of Christ, we are the Israel of God, a holy nation, God’s special people, the inheritors of all the promises that God has made throughout His Word. And these promises include not only believers but also our children. Nations include children; peoples include infants. And so God always establishes his covenants with generations. He covenants with Noah and his descendants; with Abraham and his descendants; with the Israelites who stood at the foot of Mt. Sinai and with all their descendants after them; with David and his descendants. And the New Covenant into which we are incorporated is no different. God welcomes believers and their children into this organic community, this Church which He is building, and calls all to love Him, to trust Him, and to serve Him with joy and reverent fear. So we baptize —— because God extends His promise to this child even as He extends His promise to us.

So what is this promise? It is a promise that God will be our God and we His people through faith in Christ. God promises in the waters of baptism that though we have rebelled against Him, though we are by nature stones, He will forgive us through the sacrifice of Jesus on the Cross and will make us living stones by pouring out His Spirit on us. The waters of baptism promise these very things – even as water cleanses the body, so the blood of Jesus sprinkled upon us cleanses us from our sin – hence, sometimes baptism is by sprinkling; even as water is the source of life, so the Holy Spirit poured out upon us grants us new life in service of God – hence, sometimes, as today, baptism is by pouring.

Forgiveness and new life are the promises God holds out this day – so as you witness this baptism and renew your own baptismal covenant, let me urge you to believe these promises.