Following up on yesterday's sermon, it's important for us to understand how much had changed in Israel leading into the time of Haggai. These were not simple times in Haggai 2, because the people of Israel were not really in a place to do what their ancestors had done: most of the people gathered for the dedication of the new Temple were born after the original had been destroyed. Many had come back from Babylon, where their songs had been much more akin to Psalm 137 than Psalm 24.
Additionally, it is worth remembering that we often see the past in what I've heard called "rosy retrospection." That is, we look back and think things were far better than they were: we remember the good parts, but one can turn the pages back to the end of 2 Kings and know that things in Jerusalem were not good at all when the Exile came. One can, and should, weep over the loss of good things from the past, but be careful to remember all the aspects of the past and do not weep for that which was wrong. We can, in our day, rightly weep that the time has gone in which you could leave your doors unlocked or when firearms at school were probably squirrel guns left in the truck in the parking lot. These losses are tragic.
It is not tragic, however, to have lost racial segregation or to have empowered women to flee abusive marriages--both of which are changes in law and social habits that started in the late 20th century as the sad changes happened. Be careful not to weep over things which are not worthy of it. The Israelites would have been right to weep over losing the Temple, but they should also have remembered it was their own idolatry that brought the Exile and destruction in the first place.
Further, looking ahead, we do have to separate what was the clear work of God in bringing the Messiah from what is our responsibility. God brought the greater glory to the Second Temple through bringing Jesus. We will not see the Messiah come back quite the same way, so this batch of events and promises is more about helping us see how God has worked in the past and draw hope and inspiration, rather than a template going forward.
Because God does continue to work, even in the days when it looks like there is very little left to work with.