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.

At His birth, what message did the angel bring to the shepherds abiding in the field?
How extensively did Christ make use of parables?
In what psalm was the resurrection of Christ foretold?
2. What did God tell Adam and Eve would he the result if they transgressed, and partook of the forbidden fruit?
With what words did God admonish Cain?
For whose sake did Christ say the period of papal persecution would be shortened?
Where is this city, and what is it called?

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