Now I think no sober person will be in doubt how rashly they stir up Christ’s church with their altercations and contentions over infant baptism. But it behooves us to note what Satan is attempting with this great subtlety of his. He is trying to take away from us the singular fruit of assurance and spiritual joy which is to be gathered from it, and also to diminish somewhat the glory of the divine goodness. For how sweet it is to godly minds to be assured, not only by word, but by sight, that they obtain so much favor with the Heavenly Father that their offspring are within his care? For here we can see how he takes on toward us the role of a most provident Father, who even after our death maintains his care for us, providing for and looking after our children. Should we not, following David’s example, rejoice with all our heart in thanksgiving, that his name may be hallowed by such an example of his goodness [Psalm 48:10]?
It is precisely this which Satan is attempting in assailing infant baptism with such an army: that, once this testimony of God’s grace is taken away from us, the promise which, through it, is put before our eyes may vanish little by little. From this would grow up not only impious ungratefulness toward God’s mercy but a certain negligence about instructing our children in piety. For when we consider that immediately from birth God takes and acknowledges them as his children, we feel a strong stimulus to instruct them in an earnest fear of God and observance of the law. Accordingly, unless we wish spitefully to obscure God’s goodness, let us offer our infants to him for he gives them a place among those of his family and household, that is, the members of the church.
“For when we consider that immediately from birth God takes and acknowledges them as his children” How does this accurately reflect scripture’s testimony we are all born in original sin and separate from God, children of wrath? We are born His children? This is precisely why the entire early church baptized children, to cleanse them from original sin and the Adamic stain, so they could be His children.
There are couple reason why Calvin could do this. First, he did not believe that baptism removed original sin. Calvin was firm believer in original sin and the need to trust in Christ to remove that sin. Baptism was a sign of Christ’s work, not a guarantee that His work had been applied to the believer. Second, he did believe that baptism brought you into the church. It made you part of the covenant people of God and thus one of God’s children in that way. It was a sign of God’s grace and kindness to the child that he/she was born in a covenant home.