The covenant promise affords the only certain and objective ground for the baptism of infants. But if the question is raised, how infant baptism can function as a means of grace to strengthen spiritual life, the answer is that it can at the very moment of its administration strengthen the regenerate life, if already present in the child, and can strengthen faith later on when the significance of baptism is more clearly understood. Its operation is not necessarily limited to the very moment of its administration.

Berkhof’s Summary of Doctrine