John Chrysostom
What then? Is one here and another there? How then does he say, "Whose voice then shook the earth"? The earth was shaken by the voice of Him who then gave the law. "And who now has given this promise: Yet once more I will shake not only the earth, but also heaven." Thus everything will be changed and ordered from above for the better. This is expressed by the words cited here. Why then do you grieve, suffering in a temporary world and enduring distress in a swiftly passing world? If there were uncertainty in the future destiny of the world, then one awaiting the end would have reason to grieve.