The Salt Lake Temple Alpha and Omega Scroll Stone
There is a stone carving of a scroll on the keystone over the first window on the center tower of the east and west faces of the Salt Lake Temple. The scroll has a gilded inscription on it, which reads, "I am Alpha and Omega".
The keystone is a symbol that represents the priesthood and the New and Everlasting Covenant.
In ancient times, the prophets and inspired writers recorded the scriptures on scrolls, (example Jeremiah 36:2). So the stone scroll on the temple is symbolic of the Word of God.
The inscription I Am Alpha and Omega is a reference to Jesus Christ. In the New Testament, Jesus refers to himself as "I Am" (John 8:58), indicating that He is Jehovah, the God of The Old Testament. In Revelation 22:13, Jesus is called Alpha and Omega. Alpha is the first letter in the Greek alphabet and Omega is the last. These words are used figuratively to teach the eternal nature of Jesus' existence. Elder Bruce McConkie explains, "He was God in the beginning (John 1:1-3); he is God now; he will be God in the end, that is to all eternity. The beginning is the pre-existent eternity that went before; the end is the immortal eternity that is to come." ("Mormon Doctrine" p. 55)
Inscribing Jesus' names on the temple designates that the temple is His. If it was someone else's temple then their name would be on it.
The keystone, scroll and inscription combined suggests that the temple is where the words and blessings of Christ are given by authority of His priesthood.