About Quinn: he is as credible to Mormons as is Hans Kung to Catholics. He was once widely read by the Saints, he’s scholarly, and LDS liberals may still appreciate some of his works, but mainstream Mormons generally discount him. He was excommunicated for some of his later work. which the LDS Church felt was likely to create confusion among the faithful.
Mormons do not see Matthew 16:18-19 as a promise that the ‘gates of hell’ will NEVER prevail against the Church. Rather, because they believe the ‘rock’ upon which the Church was to be built to be the rock of faith–they felt the Church only remained on the earth so long as true faith remained. With the Great Apostasy and the persecutions of the late first century and continuing, faith was lost and had to be ‘restored’ by the direct power of God. Hence, Mormons are as fascinated with Apostolic Succession as are Catholics–they just trace their ‘succession’ back to 1829 or so, when Apostles holding the Keys of that succession were allowed to come to Joseph Smith and a few followers and restore it. James Talmage, a classic LDS writer of about the same era as GK Chesterton and CS Lewis, has written about this in topic “The Great Apostasy”. See also his other two great works: “The Articles of Faith” and “Jesus the Christ” for a good overview of LDS theology.
Chances are that at least some of you visiting with LDS missionaries could ask about their ‘priesthood line of authority’: many Mormons carry their lineage of succession in their Scriptures. It is one of two things which Mormons carry about with them with great pride. This and their recod of Temple endowments, and their Patriarchal Blessing, which amounts to a chapter or so of latter-day Scripture addressed personally to them from God.
It is important to realize that ‘personal revelation’ is far more important to Mormons than evidence. Everyone is entitled to some measure of personal revelation, depending upon their station in life. As non-Mormons, you are entitled to pray and receive personal revelation that the Book of Mormon is true, the LDS Church has a Living Prophet and true Apostles, etcetera. A baptised Mormon father or mother can receive revelations on behalf of their own families, to the degree this does not interfere with ‘free agency’, another vital concept in Mormon theology. Appointees to various Church offices are entitled to a measure of revelation on behalf of those they serve. A patriarchal blessing is received once in a lifetime, at an LDS temple–which is NOT synonymous with either the usual LDS Meetinghouse NOR with the Mormon Tabernacle from which the Choir sings. It is similar to the blessings bestowed in Old Testament Scriptures, as from Abraham upon Issac, Isaaac upon Jacob, etcetera.
However, revelation must also be ‘received’ by it’s intended in order to be validated: my ‘revelation’ on your behalf must be prayed over and accepted as such by you, or a problem exists. Either I am receiving false revelations or you are not in harmony with the Spirit. Normally, rank pre-eminates: as your Bishop (like a pastor), my ‘revelation’ should be received by you humbly, since it is most likely that I and not you are in harmony with the Holy Spirit. This does NOT give me license to excercise ‘unrighteous dominion’ however–if my ‘revelation’ clearly violates other revealed truth, for example, it would be I who would be in trouble. I could not make an untoward suggestion as a ‘revelation’ to a female member under my care for instance. Nor, as a husband, could I employ ‘personal revelation’ as a foil against my spouse, though allegations abound that it is attempted at times. (This seems to me an inherent bias against tradtional ‘patriarchal’ Christian-style households in general, and not a criticism exclusive to the LDS).