TarkanAttila, Revelation is an important piece of the foundation. It is not the only piece however. The church is also built on prophets and apostles with Christ himself being the chief cornerstone (see Eph 2:20). That is why we have apostles and prophets today.
Priesthood is another important piece. From before the creation of the world priesthood was held. It was given to Adam and passed down to the present day.
Another piece was ordinances. Baptism and the laying on of hands for the gift of the Holy Ghost among others.
I don’t know that were in disagreement much here. I’m sure we could argue about the details of what I am saying but probably not the main points.
But… prophets and apostles operate on personal revelation… (Unless a “prophet” or “apostle” means something other than “one who receives a direct message from God and teaches it” and “one of the original 12 who received witnessed, followed, and revelations from Jesus whilst He was in the world” respectively.)
And while I agree Catholic priesthood, baptism, and the other Catholic sacraments are all important to the faith, we’re talking theologically. And while the priesthood and the sacraments are indeed theological in nature, primarily the Roman Church receives Her theology from Tradition.
Tradition includes Sacred Scripture (the writings of the Apostles themselves), the Traditions of the Church declared authoritatively after the Apostles (including Mary being the Mother of God, and the monotheistic Trinity), and the teaching authority of the Church driven by the Pope (apostolic descendant of Peter), and the patriarchs, archbishops, and bishops (apostolic descendants of the Apostles).
In short, the Apostles - whom Christ instituted as the Church - drive the theology of the Roman Church in whole.
Unlike Mormons, we believe Apostolic Succession means that what the Apostles taught is what we are to believe. Looking at history, we can only determine that what the Apostles themselves taught has been preserved since the beginning. There never was a total apostasy, and therefore the Church of Rome - as well as the Church of Constantinople, and its dependent Churches - teach today what Christ taught the Apostles, and the Apostles, consequently, taught theirs. We are built on Christ’s Church - the Apostles - and not for one second do we believe Christ abandoned us to Hell, much less for 1000-2000 years (before Joseph Smith and his peepstone came along).