I think you're making a bigger deal about the mysteries than is warranted.
The apostasy was so complete, that you clearly have no idea what I am even talking about. Protestant Christianity is just as ignorant as Catholic Christianity when it comes to the mysteries. They were never put in the Bible, because they were deemed to sacred for inclusion. Jesus taught the apostles a series of rites after his resurrection, rites which are not mentioned nor described in the Bible. One such rite, is the rite of the Bridal Chamber. It is mentioned in our oldest extent Christian literature, the Nag Hammadi Library, but it is not being practiced in any church today save the LDS church.
There is another ordinance, which could hardly be classified as a mystery, and which is mentioned in the Bible - that is only practiced by the Mormons. It is called the healing of the sick. It is performed by the Elders of the church, through the laying on of hands; the Elders pray over the person, and anoint them with oil. (James 5:14) An apostle of God did this to me, and healed me of an incurable disease, after I was given two years to live by the medical profession. It is a simple and beautiful demonstration of true priesthood power, but it has been replaced with a lot of pagan nonsense - relics that could heal, graven images, beads with mystical powers. From that poisoned well, sprang most of the churches of today.
As far as the deification of mankind, as Katzpur has so graciously provided, it can be found in Revelations 3:21. The throne is the symbol of the power and authority of God, and to share it is certainly to become a god. Any other interpretation would diminish this verse substantially. It was also taught by the most prolific Christian writers of the first few centuries, before it fell out of fashion. You see once doctrines are established by common vote, they change like fashions, according to the whim of the clerics and bishops. Here are some quotes concerning deification from some of the Fathers of the Christian faith:
"The Word was made flesh in order that we might be enabled to be made gods. . . . Just as the Lord, putting on the body, became a man, so also we men are both deified through his flesh, and henceforth inherit everlasting life."
(Athanasius, Against the Arians, 1.39, 3.39. )
"But he himself that justifies also deifies, for by justifying he makes sons of God. 'For he has given them power to become the sons of God' [John 1:12]. If then we have been made sons of god, we have also been made gods."
(Augustine, On the Psalms, 50:2).
"yea, I say, the Word of God became a man so that you might learn from a man how to become a god."
(Clement of Alexandria, Exhortation to the Greeks, 1).
I'm not sure what you mean by baptism being a covenant.
Of course. Apparently you didn't understand when I said the knowledge was lost. Originally, baptism was the demonstration of a covenant, where the initiate repents of all his sins and covenants with God to keep his commandments. In return, God grants the forgiveness of sins. The initiate becomes an Israelite, adopted in to the lineage of Abraham, through which the entire world will be blessed. The Temple of Solomon had something like 40 baptismal fonts, the grandest of which stood on the backs of twelve oxen, which represented the twelve tribes of Israel.
I do agree that Jesus submitted to the Father Hebrews 5:7
Yes, he did in many places. Yet the Catholic creed of the Trinity denies any such relationship, putting them as equals. This is the only Catholic creed that was adopted by the Protestant Reformation.
Ephesians 3:4, 9. Colossians 1:26-27
These mention the mystery of Christ, but I don't believe they are referring to the Christian Mysteries.
The Holy Spirit remained and so did God's word. The writings and mysteries are still with us. The mysteries and knowledge of Christ did not depend on the apostles staying alive.
The Holy Spirit didn't remain. By the time Joseph Smith was born, not one church claimed to have it. The miracles and signs also disappeared, as the world slipped into a long dark night. The early church was very concerned over the loss of the miracles. Tertullian, who lived in the 2nd century, taught that the apostles could do all the same miracles that Christ did. He also wrote that the spirit of the Holy Ghost, and the miracles survived the death of the apostles, but this didn't last long. By Origen's day, there were only "traces" of these supernatural gifts. With rare exception, by the 3rd century AD, there were no mentions of miracles, speaking in tongues, prophecy, revelation, or any gifts of the Spirit. According to the historian Paul Johnson, who wrote The History of Christianity, the Christian world acknowledged that the age of miracles was over.
