The Bible Answers this as "No"
Quoting you (all quotations are from prior to editing the "tone" of the question):
Is the Urantia Book ("White Stone") foretold in The Book of Revelation
2:17 ?
There is no textual evidence to link the "white stone" symbol to the Urantia Book. Such a connection is an arbitrary assertion. Of course, because we are dealing with symbolism and prophecy here in Rev 2:17, something that was future is being referred to in a symbolic way. The question then becomes, does the Bible give evidence that it cannot be the Urantia Book, based off what is known from both Scripture and the teachings of that book itself? The answer to that is "Yes," the Bible has textual evidence that proves the Urantia Book cannot be the "white stone" of Revelation 2:17.
Quoting you:
Rev 2:17 He that hath an ear, let him hear what the Spirit saith unto
the churches; To him that overcometh will I give to eat of the hidden
manna, and will give him a white stone, and in the stone a new name
written, which no man knoweth saving he that receiveth it. (KJV)
"He that hath an ear..." Is that us ?
The reference "he that hath an ear" refers back to
Rev 1:3 (emphasis added):
Blessed is he that readeth, and they that hear the words of this
prophecy, and keep those things which are written therein: for the
time is at hand.
It is the Apostle John (the author of Revelation) that God earlier related in John's gospel who it is that can "hear":
John 8:42-44 (emphasis added):
42 Jesus said unto them, If God were your Father, ye would love me:
for I proceeded forth and came from God; neither came I of myself,
but he sent me. 43 Why do ye not understand my speech? even because
ye cannot hear my word. 44 Ye are of your father the devil, and the
lusts of your father ye will do. He was a murderer from the
beginning, and abode not in the truth, because there is no truth in
him. When he speaketh a lie, he speaketh of his own: for he is a
liar, and the father of it.
Those that can hear Jesus' words (the same one speaking in Revelation; Rev 1:1-2) are those that "love Jesus," and John's words are by His Spirit (Rev 1:9-11) in the passage under discussion.
Quoting you:
"let him hear what the Spirit saith..." If the Spirit says it. Can we
get any more authoritative than that ?
No, we cannot. But all that the Spirit is saying is what is written in the book of Revelation, and specifically in this reference to what was said in Rev 2:12-16 to "church in Pergamos."
Quoting you:
"To him that overcometh..." We have to overcome. But overcome what?
Do we, at least to some degree, have to "overcome" what we already
believe, our previously settled beliefs derived from the Bible?
Specifically, what was it that, not we, but the believers in the "church in Pergamos" had to overcome (since they are the direct reference and recipients of the message)? The temptation amidst Satan's stronghold to deny "my [Jesus Christ's] name," which meant to have "denied my faith" (Rev 2:13). It was false doctrine about Christ that had to be overcome, which doctrine had been allowed in their midst (Rev 2:14-15).
That principle can be translated to a "we" (i.e. believers in Christ today), that false doctrine should be resisted, not allowed in the church itself, and certainly not believed. So on the contrary, it is in fact "previously settled beliefs derived from the Bible" that should be maintained.
Quoting you:
"will I give to eat of the hidden manna" Could the hidden manna the
new truth revealed in The Urantia Book ?
The book of Revelation answers this as well
Rev 22:18-19:
18For I testify unto every man that heareth the words of the prophecy
of this book, If any man shall add unto these things, God shall add
unto him the plagues that are written in this book: 19And if any man
shall take away from the words of the book of this prophecy, God shall
take away his part out of the book of life, and out of the holy city,
and from the things which are written in this book.
While it is debated among conservative Christians whether the warning in the passage is a reference to the Bible as a whole, or to just the subset portion of the Bible that is the Book of Revelation, for your question, that does not matter, as it is the Book of Revelation under discussion. What it does say is to not "add" or "take away," it is not approved by God.
Quoting you:
"and will give him a white stone"
Throughout history the "white stone" has signified "yes" or the truth.
Could the Urantia Book be the "white stone," signifying The Truth.
As answers here on BH.SE note, the "white stone" likely deals with admission into a place (and thus into Christ's kingdom as argued in a couple of those answers there). However, even if it did symbolize Truth, Christ has already declared that He Himself is that Truth (Jn 14:6), and that His word is that Truth (Jn 17:17), and (as noted above) the book of Revelation was the final word on that Truth with respect to prophetic events.
(It is worth noting that these connections are all from the same human instrument of God's divine Revelation, the apostle John; not that any of God's revelation will contradict, but for those that hold more weight to examining how a particular human author uses terms and such, we are dealing with the same author).
"and in the stone a new name written"
That "new name written" written in the Urantia Book is "Michael of
Nebadon", Jesus' heavenly, spiritual name. Along with this "new name
written" is the complete, previously unknown and unrevealed story of
Jesus as Michael. About 1/4 of the Book. Michael is not an archangel
according to the Urantia Book. The Book of Daniel describes Michael as
"one of the chief princes," and "Michael your prince," and
"Michael..., the great prince." A prince is not an archangel. A prince
is the son of the king, and a member of the Royal Family.
Jesus/Michael is mentioned as a divine Son of God and we can learn all
about Him in The Urantia Book, apparently the "white stone."
"which no man knoweth saving he that receiveth it."
The only ones who can know it are those who receive it, the acceptance
of the Urantia Book.
To assert this is "Michael of Nebadon" is simply that, an assertion. Is it true? Not based off the language of Scripture. This new name is only known by two people, the one giving the stone and the one receiving it. The words are singular "no man" is οὐδεὶς (lit: "no one") with one exception given, "he that receiveth it," which is ὁ λαμβάνων (lit: "the one receiving." It is thus not a new name for Christ, but rather for the believer. If it were a new name for Christ, then every believer would be receiving the same name, and there would be many more than just the one receiving it knowing it.
Additionally, you state "Michael is not an archangel according to the Urantia Book," yet according to the Bible, and that quite clearly, he is, and not the same as the Lord.
Jude 9:
Yet Michael the archangel, when contending with the devil he
disputed about the body of Moses, durst not bring against him a
railing accusation, but said, The Lord rebuke thee.
If the current Wikipedia article is accurate in reflecting the teachings of the Urantia Book, then the following are some other points of conflict with the Bible:
Some differences with Christianity include:
- Jesus' crucifixion is not considered an atonement for the sins of humanity. The crucifixion is taught to be an outcome of the fears
of religious leaders of the day, who regarded his teachings as a
threat to their positions of authority.
- Jesus is considered the human incarnation of "Michael of Nebadon," one of more than 700,000 "Paradise Sons" of God, or "Creator Sons."
Jesus is not considered the second person of the Trinity as he is in
Christianity. The book refers to the Eternal Son as the second person
of the Trinity.
- Jesus was born on earth through natural means of conception instead of a virgin birth.
- Jesus did not walk on water or perform some of the miracles that are attributed to him in the Bible.
I'll leave the Trinity point alone, as that will get too far into theology for what this site likes (since there is no direct assertion of the doctrine, though I believe the text of Scripture supports the doctrine in many ways). However, the other three points can be shown to directly contradict the textual assertions of the Bible, because:
- Jesus is at least the "propitiation" and "reconciliation" for sins (1 Jn 2:2; Heb 2:14-17); both concepts fall under the idea of "atonement," and are certainly relating Christ's death to more than just being feared by religious leaders of the day.
- Jesus was born of a virgin (Mt 1:23-25; the Greek is παρθένος which is primarly related to the concept of virginity as we know it, and is affirmed in the phrasing of Joseph's behavior toward her, that he "knew her not" (a euphemism for sexual contact, as some translations reflect, and numerous commentaries discuss).
- Jesus is stated to have walked on water (Mt 14:25-26)
It becomes a bit hypocritical to use the Bible's statement of Rev 2:17 to try and support the Urantia Book, when the Urantia Book itself ignores the revelation of the Bible at these other points. Proper hermeneutics never ignores the testimony of the text itself.
Conclusion
So the Urantia Book's "revelation" proves to be exactly what Rev 2:12-16 warned against: lies leading one away from Christ, and thus cannot be the "white stone" of Rev 2:17.