815. Rabbi Yitzchak opened the discussion with the verse, "And they came to the threshing floor of Atad...and when the inhabitants of the land, the Canaanite, saw the mourning at the floor of Atad" (Beresheet 50:10-11). We have to examine these verses. Why should it concern us that they came to the threshing floor of Atad, and why was it named "the mourning of Egypt." It should have been named 'the mourning of Yisrael,' so why Egypt?
822. When Jacob died they rejoiced THAT NOW THEY WOULD BE ABLE TO ENSLAVE YISRAEL. They looked to see what would become of it and saw the threshing floor of Atad, the prevailing punishment, as 'Atad' has the same numerical value as 'hand,' mentioned in the verse, "And Yisrael saw that great work (lit. 'hand') which Hashem did upon Egypt" (Shemot 14:31). When they came to this place, they saw the mighty acts coming from Atad UPON THEM, NAMELY THE TEN PLAGUES OF EGYPT AND THE PARTING OF THE RED SEA. Why is it called Atad (Eng. 'thorn-bush')? As the thorns grow on both sides of the thorn-bush, so do the fingers of the hand, each containing numerous Gvurot, punishments and decrees. Hence "they mourned with a great and very sore lamentation...so that the name of it was called the mourning of the Egyptians." This was truly a grievous mourning for the Egyptians, and no one else.
850. Rabbi Shimon opened the discussion saying, "And they came to the threshing floor of Atad" (Beresheet 50:10). HE ASKS, What is the threshing floor of Atad? HE ANSWERS, It is an allusion to the dominion of Egypt, which is removed. The threshing floor of Atad is the dominion of Egypt which passed to give way to the dominion of Yisrael. For they saw a threshing floor, WHICH ALLUDES TO THE REIGN OF YISRAEL, as in "having put on their robes, in a threshing floor" (I Melachim 22:10). Therefore "they mourned with a great and very sore lamentation."