Midrash su Deuteronomio 33:17

And I have oxen. This implies that I have no need to fear you (he was thinking to himself), for now Joseph is born, who is called an ox, as is said: His firstling ox, majesty is his (Deut. 33:17). Asses. The word ass alludes to the Messiah the son of David, as it is said: Lowly and riding upon an ass (Zech. 9:9). Flocks refers to the merit of the tribes, whose descendants will be called flock, as is said: And ye My sheep, the flock of My pasture (Ezek. 34:31).

R. Jochanan said in the name of R. Simon b. Jochai: "What does the passage (Is. 32, 20) Happy are ye that sow beside all waters, freely sending forth the feet of the ox and the ass, mean? Those who occupy themselves with the study of the Torah with loving kindness will be rewarded with the inheritance of two tribes; as it is said (Ib., ib., ib.) Happy are ye who sow. Sowing, refers to charity, as it is said (Hos. 10, 12) Sow then for yourselves after righteousness, that you may reap [the fruit] of kindness. Water, refers to the Torah, as it is said (Is. 55, 1) Ho, everyone of ye that thirsteth, come ye to the water — will be rewarded with the inheritance of two tribes; i.e., he will be rewarded with a canopy [of honor] as Joseph was, concerning whom it is written (Ex. 79, 22) Joseph is a canopy [of honor] … the daughters [of Egypt] run over the walls; and he will also be rewarded with the inheritance of Issachar, concerning whom it is written (Ib.) Issachar is a strong-boned ass. Others explain this to mean that he will overcome his enemies as the tribe of Joseph, concerning whom it is written (Ib., ib. 17) With them shall he push nations together to the ends of the earth — and he acquires understanding as the tribe of Issachar, concerning whom it is written (I. Chr. 12, 32) And of the children of Issachar, those who had understanding of the times to know what Israel ought to do."

(Ib. 1, 15) And the King of Egypt said to the Hebrew midwives. Raba and Samuel both explain this passage: The former said: "It was a mother and a daughter," the latter said: "It was a mother-in-law and daughter-in-law." The one who interprets it as a mother and daughter refers to Jochebed and Miriam and the other who means a daughter-in-law and mother-in-law refers to Jochebed and Elisheba. We find a Baraitha that is in accordance with the one who explains it as the daughter and mother; for we are taught in the following Baraitha, Shifra refers to Jochebed. Why her name Shifra? Because she smoothened the limbs of the infant. It may be explained in another way; because Israel multiplied itself during her days Puah refers to Miriam. Why was she called Puah? Because she would speak to the infant [and play with it] in order to pacify it. Another explanation might be given to it, because she spoke through a Holy Inspiration and said: "My mother is destined to give birth to a son who will save Israel." (Ib., ib. 16) And He said: "When do the office of a midwife to the Hebrew women you shall have due regard upon the birth." What does that mean? Said R. Jochanan: "He gave them a great sign [how to recognize the time of a woman when she is about to give birth to a child]." (Ib., ib., ib.) If it be a son, then shall ye kill him; but if it be a daughter then shall she live. Said R. Chaninah: "An important sign did Pharaoh reveal unto the midwives; the birth of a son comes with the face downward, while the birth of a daughter comes with the face upward." (Ib., ib. 17) But the midwives feared God and they did not do as the king of Egypt commanded them, but they saved the male children. We are taught that not only did they not kill the male children but they would supply them with water and food in order to sustain them. (Ib., ib. 19) And the midwives said unto Pharaoh, because the Hebrew women are not as the Egyptian; for they are Chayoth. What is the meaning of Chayoth? Should we say that they are midwives themselves, does not a midwife need another midwife for her own giving birth? We must therefore say, they said to him: "This nation (Israel) is likened unto beasts. Juda, as is said (Gen. 49, 9) Like a lion's welp, O Juda; (Ib., ib. 17) Dan shall be a serpent by the way. (Ib., ib., 21) Maphthali is like a fleet hind, (Ib., ib, 14) Yesachar is a strong-boned ass, (Deut. 33, 17) Joseph, as first born steer is adorned with glory. (Gen 49, 27) Benjamin shall be as a wolf that rendeth. Concerning the above it is written in detail what they are and concerning the rest of the tribes, it is written in general (Ez. 19, 2) And so, what a noble lioness was thy mother! among lions did she lie down amidst lions did she raise her whelps."