On how what’s already happened?
xjcsa to philetus
Don’t let anyone deceive you in any way, for that day will not come until the rebellion occurs and the man of lawlessness is revealed, the man doomed to destruction. He will oppose and will exalt himself over everything that is called God or is worshiped, so that he sets himself up in God’s temple, proclaiming himself to be God (2 Thessalonians 2:3-4).
I don’t know how this can be if the Temple is not rebuilt.
Already happened.