The Gemara states that every day Hashem is angry for just one "רגע", literally 'a moment'. How long is a moment? The Gemara attempts to calculate this entity but ultimately it is a relative calculation and does not tell us much since we can never know when it starts.
We find this 'moment' reappearing prominently in the upcoming haftorah for Parshat Ki Teizei:
ברגע קטון עזבתיך וברחמים גדולים אקבצך
בשצף קצף הסתרתי פני רגע ממך ובחסד עולם ריחמתיךFor a small moment have I forsaken thee; but with great compassion will I gather thee
In a little wrath I hid My face from thee for a moment; but with everlasting kindness will I have compassion on thee (Isaiah 54, ישעיה נ"ד)
The fact that our lack of divine protection/supervision only lasted a short 'moment' is supposed to be consoling.
However, this is not necessarily self evident. The amount of destruction that can be inflicted in just a 'moment' can be downright horrifying. Just think of a nuclear explosion, or a giant comet colliding into Earth. Theoretically the whole world can be destroyed in practically one instant. It is so much easier to destroy than to build. Years of toil and hard work can be obliterated in the blink of an eye. These were just some of the thoughts I remember racing through my mind as I watched the Twin Towers collapse on the mind numbingly tragic 9/11.
How then is this supposed to be reassuring?
I think the key to the answer lies in the two pesukim brought by the Gemara to prove this concept. Starting with the second one which reads:
לך עמי בא בחדריך וסגור דלתיך בעדיך חבי כמעט רגע עד יעבור זעם"Come, my people, enter thou into thy chambers, and shut thy doors about thee; hide thyself for a little moment, until the indignation be overpast" (Isaia 26, ישעיה כ"ו)
What this passuk shows is that it is possible to 'hide' from God's wrath. It doesn't matter if we are talking about hiding literally or figuratively, the point is that the possibility exists. This is true because the 'moment' is finite. God's love on the other hand is not.
כי רגע באפו חיים ברצונוFor His anger is but for a moment, His favour is for a life-time (Psalms 30, תהילים ל')
This first proof-text brought by the Gemara, one we say every day at the beginning of our davening, expresses just that. Hashem's will is everlasting and in favor of life. His wrath is 'only a moment'.
It doesn’t really matter exactly how long the 'moment' lasts, the important thing is that it is always finite. Much may be lost and there may be an enormous hole in our heart, but as long as we are sure that the 'moment' is finite, we know that the destruction will never be complete. There will always be a ray of hope ready to spring up from an unexpected hideout. This may not be comforting on a personal level, but on a national level it holds a great promise, upholding the everlasting covenant between God and mankind.