Chasidut zu Jechezkiel 7:2

And this is the aspect of Shabbat HaGadol, which is the name of the Shabbat before Passover, on account of the miracle, etc. The essence of the miracles and wonders that took place during the Exodus from Egypt - which crumbled the battles and nullified nature and revealed His Blessed Providence to the world - all of it was drawn from the aspect of Shabbat, which is the Future World which is totally Shabbat. From there, Hashem Yisbarach drew, so to speak, divine providence from the ends of the earth, etc., corresponding to (Ezekiel 7:2) "an end! The end has come", etc., as is brought there in the lesson as seen above. The essence of the Exodus from Egypt is drawn from Shabbat, which is the aspect of the World to Come. Therefore, Pesach is also called Shabbat, as it is written (Leviticus 23:15) "And you shall count for yourselves, from the morrow of the rest day"; in other words, Pesach, which our Sages of Blessed Memory said (Menachos 65b) that the essence of the power of the miracle of Passover is drawn from Shabbat, as explained above. This is the aspect of the Shabbat that is before Passover, which is called Shabbat HaGadol because of the miracle. For all of the miracles of the Exodus from Egypt were drawn from the aspect of Shabbat, as explained above. Therefore it is called "Gadol" because of the miracles which were called the aspect of Gadol (great), as it is written (II Kings 8:4) "Please tell me all the great things that Elisha performed". As Rabbeinu z"l wrote there in the lesson as seen above, 'And 2 tears went down into the great sea', see there.