17 And Jesus answered and said unto him, Blessed art thou, Simon Bar-jona: for flesh and blood hath not revealed it unto thee, but my Father which is in heaven.
18 And I say also unto thee, That thou art Peter, and upon this rock I will build my church; and the gates of hell shall not prevail against it. (Matthew 16).
Before you can build a structure, you have to dig down to a bedrock to pour your foundation, and that bedrock is communication from Heavenly Father via the Holy Ghost and through the priesthood.
Next up: 20 ...And are built upon the foundation of the apostles and prophets (Ephesians 2).
All measured off of: ...Jesus Christ himself being the chief corner stone; (Ephesians 2:20).
We are the only ones who claim a foundation of apostles and prophets being built in these last days, in harmony with the bible (which Christianity claims to follow - though the scriptures themselves say you aren't built upon the bible but upon revelation....), and with the fruits one would expect from apostles and prophets, new scriptures, temples, missionary work and so on.
But what is the Book of Mormon in it all?
Concerning this record the Prophet Joseph Smith said: “I told the brethren that the Book of Mormon was the most correct of any book on earth, and the keystone of our religion, and a man would get nearer to God by abiding by its precepts, than by any other book.” (Book of Mormon Introduction).
A keystone is not what a structure is built on, but without which, an archway of the stone-building type, cannot stand.
I'm certain there is more symbolism here but for now I just thought I'd share something I put together in learning.