Shabbat Hagadol - Derasha from 1940

There are two versions to the portion of the Seder that discusses the "bread of affliction": "This is the bread .."; "Like this bread …". When Bnei Yisrael are in a time of tranquility, it is appropriate to say: "Like …," as it serves as a reminder of what once was. In difficult times, that bread represents our present state. If we are to consider our present state, it is a wonder that we can celebrate a holiday of freedom, but we cannot push it off to some other time. The answer to our feeling is Shabbat Hagadol.
It is not just that historical Shabbat before liberation that was great, for the greatness of Shabbat is not mainly what is clear but what is hidden. All of the Shabbat experiences that our nation had came together and were a "great Shabbat"; they ensured the liberation, making the people fit for that greatness. "They possessed scrolls from their forefathers, which they would enjoy from Shabbat to Shabbat, when they rested, saying that Hashem would liberate them" (Shemot Rabba 5:18).
What is the secret of a nation that powers try to enslave and destroy with all sorts of clever plans and to erase hope of freedom, but do not succeed? It is Shabbat. The gray weekdays may be days of suffering and low spirits. Shabbat, though, is a day of rest and light, not only of the candles but of the spirit. The light reminds the people of the words of their parents from their childhood and the bright past when the forefathers lived in their homeland; these give hope for a brighter future. It brightens the spirits and raises the stooped backs, as people hold on to faith in the future liberation. A father tells his son and a mother whispers to her daughter: "He will certainly redeem."
If during the week, "These are idol worshippers and those are idol worshippers" (see Shemot Rabba 21:7), "Whoever observes Shabbat properly, even if he worships idols like the generation of Enosh, he will be forgiven" (Shabbat 118b). Shabbat contains a wonderful power that can destroy idol worship, for belief in the Creator of All gives light to the depths of the spirit, which can help it climb out of its deterioration. While the Egyptians physically enslaved and tortured, the purity of the heart was the possession of those oppressed. There is no need to be jealous of the oppressor but to have a feeling of disdain and lack of regard for him.
Shabbat gave the power to the spirit to oppose the idol worship of Pharaoh: "The Nile is mine and I made myself" (Yechezkel 29:3). The bravery of the specific Shabbat Hagadol, where the Israelites took sheep, one of the idols of Egypt, and prepared to slaughter them, was able to make us fit for the liberation. It was all the previous Shabbatot that made this attitude possible and prepared the people to "smash the idols."
If we will merit to soon see a nation of freed people marching vigorously toward a glowing future, it is due to the historical Shabbat Hagadol and the greatness of Shabbat, in general. This is what slaughtered the Egyptian idols and gave the people the standing they needed, and this is the proper preparation for Pesach.