The Bible makes astounding claims for baptism.
For example:
In Acts 2, Peter says baptism is for the forgiveness of sins.
In Titus 3, Paul calls baptism the washing of regeneration.
In Romans 6, Paul says we are united to Christ in his death, burial, and resurrection in baptism.
In Galatians 3, Paul says in baptism we are clothed with Christ.
And we could go on and on.
These passages led Martin Luther to ask, “How can water do such wonders?” The answer is this: it’s not the water that does these things, but God working through the water. One of the most important truths about baptism is that it is not a human work but a divine work. Yes, God uses created instruments or agents. He uses a human officiant to perform the baptism. He uses water. But baptism is God’s action. In baptism, God gives, God forgives, God unites, God promises, God speaks, God works. Of course, what God gives in baptism must be received by us in faith. But the work of baptism is God's.
When you see that baptism is God’s work, objections to baptizing babies go away. If baptism is a human work, infants can’t be baptized because infants cannot do the work. But it’s not a human work. It’s a divine work. Baptism is a gift - and infants can certainly receive a gift. (Many babies are showered with gifts at birth.) Baptism formalizes a relationship - and babies can certainly have relationships. (If every baby is in relationship with his or her mom and dad, why can't a baby be in relationship with God?) Baptism is God’s word of promise. S and M are already talking to J, and even though J cannot talk back, those words spoken to her are shaping her. S and M tell J “I love you” already. Today, in the waters of baptism, God will do the same. He will speak to J. He will make a promise to her. He will say to her in and through the water, “I love you.” That's what this baptism is all about.