Daniel 8:14-27 (KJV) And he said unto me, Unto two thousand and three hundred days; then shall the sanctuary be cleansed.
And it came to pass, when I, even I Daniel, had seen the vision, and sought for the meaning, then, behold, there stood before me as the appearance of a man.
And I heard a man's voice between the banks of Ulai, which called, and said, Gabriel, make this man to understand the vision.
So he came near where I stood: and when he came, I was afraid, and fell upon my face: but he said unto me, Understand, O son of man: for at the time of the end shall be the vision.
Now as he was speaking with me, I was in a deep sleep on my face toward the ground: but he touched me, and set me upright.
And he said, Behold, I will make thee know what shall be in the last end of the indignation: for at the time appointed the end shall be.
The ram which thou sawest having two horns are the kings of Media and Persia.
And the rough goat is the king of Grecia: and the great horn that is between his eyes is the first king.
Now that being broken, whereas four stood up for it, four kingdoms shall stand up out of the nation, but not in his power.
And in the latter time of their kingdom, when the transgressors are come to the full, a king of fierce countenance, and understanding dark sentences, shall stand up.
And his power shall be mighty, but not by his own power: and he shall destroy wonderfully, and shall prosper, and practise, and shall destroy the mighty and the holy people.
And through his policy also he shall cause craft to prosper in his hand; and he shall magnify himself in his heart, and by peace shall destroy many: he shall also stand up against the Prince of princes; but he shall be broken without hand.
And the vision of the evening and the morning which was told is true: wherefore shut thou up the vision; for it shall be for many days.
And I Daniel fainted, and was sick certain days; afterward I rose up, and did the king's business; and I was astonished at the vision, but none understood it.

This quote is by Ellen White
The Great Controversy
Pages 417,419
Cleansing the Sanctuary

But the mist important question remains to be answers: What is the cleansing of the sanctuary? That there was such a service in connection with the earthly sanctuary is stated in the Old Testament Scriptures. But can there be anything in heaven to be cleansed? In Hebrews 9 the cleansing of both the earthly and heavenly sanctuary is plainly taught..... Once a year on the great Day of Atonement, the priest enters the most holy place for the cleansing of the sanctuary. The work there performed completed the yearly round of ministration.

This quote is also by Ellen White
Desire of Age
Page 234
God reveals His secrets

The Lord God will do nothing, but He revealth His secrets into His servants and prophets. While " the secrets thing belong to the Lord our God," "though thing which are revealed belongs to us and our children forever" (Amos 3:7 (KJV) Surely the Lord GOD will do nothing, but he revealeth his secret unto his servants the prophets. Deuteronomy 29:29 (KJV) The secret things belong unto the LORD our God: but those things which are revealed belong unto us and to our children for ever, that we may do all the words of this law.) God has given these things to us, and His blessing will atdnd the reverent, prayerful studies if the prophetic scriptures.