Midrash su Salmi 52:8

"But my horn hast thou exalted like that of the reêm" (Ps. 92:10). Just as the horns of the reêm are taller than those of all beasts and animals, and it gores to its right and to its left, likewise (is it with) Menachem, son of 'Ammiel, son of Joseph, his horns are taller than those of all kings, and he will gore in the future towards the four corners of the heavens, and concerning him Moses said this verse, "His firstling bullock, majesty is his, and his horns are the horns of the reêm: with them he shall gore the peoples all of them, even the ends of the earth" (Deut. 33:17). All the kings will rise up against him to slay him, as it is said, "The kings of the earth set themselves, and the rulers (take counsel together)" (Ps. 2:2). And Israel who (will be) in the Land (of Palestine) (will experience) great trouble, but in their troubles they (will be) like a green olive, as it is said, "I am anointed with fresh oil" (Ps. 92:10).

Abraham arose and prayed before the Holy One, blessed be He, that his children should not be enslaved by these four kingdoms. A deep sleep fell upon him, and he slept, as it is said, "A deep sleep fell upon Abram" (Gen. 15:12). Does then a man lie down and sleep, and yet be able to pray? But this teaches thee that Abraham was lying down and sleeping because of the intensity of his prayer that his children might enslave || these four kingdoms, as it is said, "And, lo, an horror of great darkness fell upon him" (ibid.). "Horror" refers to the kingdom of Edom, as it is written, "And behold a fourth beast, terrible and powerful, and strong exceedingly" (Dan. 7:7). "Darkness" is the kingdom of those who darken the eyes of Israel (by preventing the observance of) all the precepts which are in the Torah. "Great" (Gen. 15:12) refers to the kingdom of Media and Persia, which was great (enough to be able to afford) to sell Israel for nought. "Fell" (ibid.) refers to the kingdom of Babylon, because in their hand fell the crown of Israel, as it is said, "Babylon is fallen, is fallen" (Isa. 21:9). "Upon him" (Gen. 15:12) refers to the Ishmaelites, upon whom the Son of David will flourish, as it is said, "His enemies will I clothe with shame: but upon him shall his crown flourish" (Ps. 132:18).