this week's Torah portion, Bo

At the close of this week's Torah portion, Bo, the Torah relates how the oppression and suffering of the Israelites in Egypt reached its height. So intense was the suffering of the Hebrews that Moses felt constrained to exclaim to G-d: "Why have You dealt badly toward this people... and You have not delivered Your people." Even Moses, who was utterly devoted and faithful to G-d, could find no explanation for the extreme misery and darkness of the Exile. Soon, however a most remarkable turn of events took place. Immediately after this darkest hour of the Egyptian exile, the process of the redemption was set in motion by G-d. When all hope seemed to have been lost, precisely then did the first rays of hope begin to shine for the Jews.It is a well-known fact that the darkest part of the night is just before dawn. Our Sages compare exile to night. So too, when the night of the Egyptian exile seemed blackest, when the suffering of the Jews reached such a degree that even Moses complained "Why have You dealt badly...," it was then that the rays of deliverance began to shine.
The Talmud states that while the other nations of the earth calculate the yearly cycle according to the rotation of the sun, the Jewish People base their calendar on the rotation of the moon. For the Jews are likened to the moon, whose light wanes and diminishes, and finally seems to disappear. But it is precisely at that point that the new moon is born, and begins to grow steadily. Jewish history throughout the ages reflects the 'lunar cycle.' In the Egyptian exile, after reaching the lowest depths of oppression, when the long night of exile seemed at its very darkest, it was then that the deliverance and renewal of hope began. Such was the case in each subsequent exile.
There is much inspiration and encouragement to be derived from the above. There are times in one's life when it seems that the "wheel of fortune" has reached the lowest point of its cycle for him. It appears to him that his situation is beyond hope. Yet he should not lose faith and fall into despair, but should bear in mind that the darkest hour of exile - of our people as a whole, as well as, the 'exile' of each individual - comes just before the start of the redemption.
Adapted from the works of the Lubavitcher Rebbe.