David writes in Psalm 139 that God saw and formed and knew all his days, when he was still in his mother’s womb. He also writes in Psalm 51 that he was full of sin when he was born, in sin when he was conceived. Life begins at conception, but so does sin. This is not something that we have medicine for. It is beyond the power of parents to remove sin. But Jesus Christ has provided the cure at the cross, and he puts the means of redemption and sanctification at our disposal. It is our calling to submit to the cure and proceed with the means of healing. So parents present their children for baptism in the church, much as they might bring them to the hospital for physical healing.
Jesus Christ established baptism just before His ascension, when He commissioned His disciples to go with His authority and make disciples by baptising them. Baptism is a sign and seal of God’s covenant of grace with us, picturing our union with Christ and washing away of our sins. We are washed in His blood, represented by the water. Jesus Christ overruled the disciples when they wanted to keep little children from Him, for of such is the kingdom of God. As we are sons of Abraham by faith in Christ, our children receive the sign of the covenant as Abraham’s children did.
This is a formal ceremony acknowledging a covenant reality: Nathan and Whitney’s child is set apart as a child of believers, to be a member of the church, to confess Christ, and to fight sin in the world, in her flesh, and from the devil. Baptism is not just our testimony of our faith at this point in time. More importantly, God places His name and grace upon His people for their whole lives. God calls us to baptize our children, and as we baptize, He calls us to trust that the Spirit undoes the spiritual deadness we are all born with, at His time and way.