Here's a little clue for you all. It's about TIME. Uriah Smith believed it HAD to do with PROPHETIC time. It could not be about TIME coming to an end because there were still events to follow. He could come to no other conclusion than it had to do with prophetic time coming to ends.

Never, in all of our questions about the Seven Thunders, has it ever been considered that the time spoken of here is DIVINE TIME. Before Creation, itself, there was a divine timetable between the Father, the Son, and the Holy Spirit. It is written that a day is as a thousand years to the Lord. We simply cannot comprehend the passage of "divine time" the way that Divinity does. However, we CAN make some conclusions based on whatever the Lord has decided to reveal to us.

The Lord is not CONSTRAINED by time.
The Lord is not CONSTRAINED BY space.
The Lord is not CONSTRAINED BY matter.

ALL of space/time/matter is accessible to the Lord at any time and at any point in space/matter. Even to this day (out day), The Lord is at work. Jesus said "I and the Father WORK." That work began AT CREATION and continues today in the same manner that it began. Once pondered upon and meditated upon in truth and in the life, there leaves little doubt that salvation began AT CREATION. Jesus was slain "from the foundation of the world".