How may one know that this does not refer to the earthly sanctuary ?

Answer

"He said unto me, Understand, 0 son of man: for at the time of the end shall be the vision." Verse 17.
NOTE - The prophetic period Of 2300, days (years) extends to AD. 1844, while the divinely appointed
services of the earthly sanctuary ceased at the cross (Dan. 9:27; Matt. 27:50,51), and the sanctuary itself
was destroyed in AD. 70, when Titus captured Jerusalem. For explanation of the period here mentioned,
see the preceding reading.

When man first transgressed, what was done to prevent him from living for ever in sin?
Through what are they to -be sanctified?
What proves that the law is an undivided whole?
9. In what statement to the woman at Jacob's well did Jesus intimate that the ceremonial system of worship would be abolished?
7. What reason does God give for the Sabbath's being an everlasting sign between Him and His people?
When will this resurrection of the saints take place?
What will the ransomed of the Lord then do?

Questions & Answers are from the book Bible Readings for the Home Circle