Nicene and Post-Nicene Fathers, Vol. III:
Doctrinal Treatises of St. Augustin: Chapter 43

Chapter 43.—Baptism and the Grace Which It Typifies are Open to All, Both Infants and Adults.

For from the infant newly born to the old man bent with age, as there is none shut out from baptism, so there is none who in baptism does not die to sin. But infants die only to original sin; those who are older die also to all the sins which their evil lives have added to the sin which they brought with them.