Although Christ wholly overcame death, yet not so completely did He destroy hell, but, as it were, He bit it. He did not free all from hell, but those only who were without mortal sin. He likewise liberated those without original sin, from which they, as individuals, were freed by circumcision; or before [the institution of] circumcision, they who had been saved through their parents' faith (which refers to those who died before having the use of reason); or by the sacrifices, and by their faith in the future coming of Christ (which refers to adults).
--St. Thomas Aquinas,
The Catechetical Instructions of St. Thomas Aquinas
