A Biblical case in point is what occurred on the Mount of Transfiguration (Matt. 17:1-9). There, God the Father's voice was heard testifying that Jesus was His Beloved Son. Moses and Elias also appeared to the three apostles and Jesus on that occasion. Later, Christ admonished Peter, James and John to "tell the vision to no man, until the Son of Man be risen again from the dead" (Matt. 17:9). Clearly he was telling them that the truths they had been taught in this glorious experience shouldn't be discussed with others.
On other occasions the Lord told his disciples "that they should tell no man that he was Jesus the Christ," (Matt 16:20, Mark 7:36, Luke 9:21). Sometimes, after he performed miraculous healings, Christ required that the event be kept secret. For instance, after healing a leper (Matt. 8:2-4), he said, "see thou tell no man," (Mark 5:43, Mark 7:36). The Lord counseled us in the Sermon on the Mount to pray and fast in secret, promising that "thy Father, which seeth in secret, shall reward thee openly" (Matt. 6:18).
In John 7:10 we have Christ going somewhere in secret, not openly. He made a clandestine journey from Galilee to Jerusalem to attend the feast of tabernacles. John's account tells us that "when his brethren were gone up, then went he also up unto the feast, not openly, but as it were in secret."
Not all of us are at the same point in our spiritual maturity. That is why Christ said, regarding his parables, that some are ready to know the mysteries of the Kingdom of heaven, but to others "it is not given" (Matt 13:11). The Bible clearly teaches that people need to be prepared for knowledge of greater truth before it is revealed. As the author of Hebrews wrote, some are still babes in Christ and are ready only for milk are not yet ready for meat (Heb. 5:12-14). How are they to receive the "meat"? In sacred places, such as the temple!
Paul, himself, when he was caught up into paradise, heard unspeakable words, which were "not lawful for a man to utter" (2 Cor. 12:4).
Nephi beheld "great things, yea, even too great for man," and he recorded that "I was bidden that I should not write them" (2 Ne. 4:25).
Surely in God's timetable there is a time that all shall be revealed. But for now our spiritual learning still comes to us line upon line, as we are ready.
When people aren't ready for the more sacred things that God has for them, they are instructed to ponder the things which they have already received before being given more (3 Ne. 17:2, 3).
This was true in Old and New Testament times, in Book of Mormon times, and is still true today. After we read and study the Book of Mormon, then we will have the sealed portion, not before.
Christ reveals his word to one when he is ready—not before. Once revealed, it is no longer secret to the one who has received the new knowledge—only to the one not ready.
The sacred instructions Latter-day Saints receive in their temples are given as a preparation for their entry into the heavenly realms of glory, after their death and resurrection. Brigham Young gave this explanation of the purpose of the covenants which Latter-day Saints make in their holy temples:
Your endowment is, to receive all those ordinances in the house of the
Lord, which are necessary for you, after you have departed this life, to
enable you to walk back to the presence of the Father, passing the angels
who stand as sentinels, being enabled to give them the key words, the signs
and tokens, pertaining to the holy Priesthood, and gain your eternal exaltation
in spite of earth and hell. (Journal of Discourses, Vol. 2, p. 31.)