In this life there are many things which prevent one from a perfect purification from one’s sins. But since no one can enter into eternal life until he is well cleansed, there is need of another Sacrament which will purify man of his sins, and both free him from sickness and prepare him for entry into the heavenly kingdom. This is the Sacrament of Extreme Unction.
[St. Thomas Aquinas, Expositio in Symbolum Apostolorum, Article 10.]
