These with full devotion I embrace, and adhere to with most entire approval; since on them, as on a four-square stone, rises the structure of the holy faith; and whosoever, of whatever life and behaviour he may be, holds not fast to their solidity, even though he is seen to be a stone, yet he lies outside the building.
Gregory is setting up the foundation of the papacy. One that is holy devoted to the scripture and has great authority over his people.