Nicene and Post-Nicene Fathers, Vol. V:
A Treatise on the Merits and Forgiveness...: Chapter 28

Chapter 28.—Baptized Infants, of the Faithful; Unbaptized, of the Lost.

Hence also that other statement: “The Father loveth the Son, and hath given all things into His hand. He that believeth on the Son hath everlasting life; while he that believeth not the Son shall not see life, but the wrath of God abideth on him.” 295 Now in which of these classes must we place infants—amongst those who believe on the Son, or amongst those who believe not the Son? In neither, say some, because, as they are not yet able to believe, so must they not be deemed unbelievers. This, however, the rule of the Church does not indicate, for it joins baptized infants to the number of the faithful. Now if they who are baptized are, by virtue of the excellence and administration of so great a sacrament, nevertheless reckoned in the number of the faithful, although by their own heart and mouth they do not literally perform what appertains to the action of faith and confession; surely they who have lacked the sacrament must be classed amongst those who do not believe on the Son, and therefore, if they shall depart this life without this grace, they will have to encounter what is written concerning such—they shall not have life, but the wrath of God abideth on them. Whence could this result to those who clearly have no sins of their own, if they are not held to be obnoxious to original sin?

Footnotes

John 3:35, 36.