"For you have the Creed and the Lord's Prayer. What can be briefer to hear or to read? What easier to commit to memory? When, as the result of sin, the human race was groaning under a heavy load of misery, and was in urgent need of the divine compassion, one of the prophets, anticipating the time of the Lord's grace, declared: 'And it shall come to pass, that whosoever shall call upon the name of the Lord shall be delivered.' Hence, the Lord's prayer. But the Apostle, when, for the purpose of commending this very grace, he had quoted the prophetic testimony, immediately added: 'How then shall they call on Him in whom they have not believed?' Hence, the Creed. In these two you have those three graced exemplified: faith believes, hope and love pray. But without faith the two last cannot exist, and therefore we may say that faith also prays. Whence it is written: 'How shall they call on Him whom they have not believed?' "
-Saint Augustine of Hippo, Chapter 7 of Enchiridion.