And if these gifts are _peculiar_, no less do they convey a singular _dignity_ and _pre-eminence_. For it follows that, as S. Paul says,[56] that all the faithful are children of Abraham, being heirs not of his flesh, but of his spirit and faith; so no one is, or can be, a part of the Church's building, who rests not on Peter as the foundation. For the same God who said to Abraham, "Thy name shall no longer be called Abram, but Abraham shall be thy name," said also to Simon, "Thou shalt not be called Simon, but Cephas;" the same God who said to the former, "In thee shall all families of the earth be blessed," said to the latter, "Upon this Rock I will build my Church." What is the source of this pre-eminence in both? To both the same objection may be made, and for both the same defence. How should blessing and adoption be propagated from Abraham, as a sort of head, into the whole body of the faithful? Because Abraham is considered as joined with that mighty Seed his offspring, whence _in chief_ and _primarily_ the salvation of all depends; because Abraham is made by _participation_ partner of that dignity which _naturally_ and _substantially_ belongs to the Seed that was to spring from him. God Himself has told us this, and His Apostle S. Paul explained it. For as we read that it was said to Abraham, "In thee shall all nations of the earth be blessed," so God Himself has told us that _in thee, by thee_, means _in, by thy seed_. Hence S. Paul:[57] "To Abraham were the promises made, and to his seed. He saith not, seeds, as of many, but as of one, and to thy seed, which is Christ." So that the divine words, "In thee shall all nations of the earth be blessed," give this meaning: "As thou shalt give flesh to my only begotten Son whom I cherish in my bosom, whence He shall be called at once 'the Son of God and the Son of Abraham,'[58] so He makes thee a partner of His dignity and excellence, whence, if not the source and origin, yet thou shalt be a broad stream of blessing to be poured out on all nations."