And each one is a partaker of this spiritual origin in regeneration; and to every one when he is re-born, the water of baptism is like the Virgin's womb; for the same Holy Spirit fills the font, Who filled the Virgin, that the sin, which that sacred conception overthrew, may be taken away by this mystical washing.
Pope Leo IA great safeguard is the entire faith, the true faith, in which neither anything whatever can be added by anyone nor anything taken away; for, unless faith be one, it is not the faith.
Pope Leo II have neither permitted, nor shall I permit, the things which have been settled by the holy fathers to be violated by any innovation.
Pope Leo IAs the world attracts us with its appearance, and abundance and variety, it is not easy to turn away from it unless in the beauty of things visible the Creator rather than the creature is loved; for, when He says, 'you shall love the Lord your God from all your heart, and from all your mind, and from all your strength' (Mt. 22:37), He wishes us in nothing to loosen ourselves from the bonds of His love. And when He links the love of our neighbor also to this command, He enjoins on us the imitation of His own goodness, that we should love what He loves and do what He does.
Pope Leo I