Midrasch zu Tehillim 60:10

RABBI ELIEZER AND THE TORAH
THE following befell Rabbi Eliezer, son of Hyrḳanos. His father had many ploughmen who were ploughing arable ground, whereas he was ploughing a stony plot; he sat down and wept. His father said to him: O my son! Why dost thou weep? Art thou perchance distressed because thou dost plough a stony plot? In the past thou hast ploughed a stony plot, now behold thou shalt plough with us arable soil. He sat down on the arable ground and wept. His father said to him: But why dost thou weep? Art thou perchance distressed because thou art ploughing the arable land? He replied to him: No. (Hyrḳanos) said to him: Why dost thou weep? He answered him: I weep only because I desire to learn Torah. (Hyrḳanos) said to him: Verily thou art twenty-eight years old—yet dost thou desire to learn Torah? Nay, go, take thee a wife and beget sons and thou wilt take them to the school. He fasted two weeks not tasting || anything, until Elijah— may he be remembered for good—appeared to him and said to him: Son of Hyrḳanos! Why dost thou weep? He replied to him: Because I desire to learn Torah. (Elijah) said to him: If thou desirest to learn Torah get thee up to Jerusalem to Rabban Jochanan ben Ẓakkai. He arose and went up to Jerusalem to R. Jochanan ben Ẓakkai and sat down and wept. (R. Jochanan) said to him: Why dost thou weep? He answered him: Because I wish to learn Torah. (R. Jochanan) said to him: Whose son art thou? But he did not tell him.

The Holy One, blessed be He, declared unto him: Inasmuch as you have said: “I will not take a thread,” I shall absolve your sons of the sins they commit at the altar around which a crimson thread will be encircled. As we have learned, the altar was encircled with a crimson thread. Furthermore, in reward for declaring: “I will not take a thread,” I will give your sons the precept of the purple fringes (on their prayer shawls). And since you said: “Nor a shoe-latchet,” I will give thy children the precepts of yebamah and halitzah: And loose his shoe from off his foot (Deut. 25:9).²²Yebamah is the law requiring a brother to marry his deceased brother’s wife when there has been no issue. Halitzah is the ceremony of throwing a shoe at the brother-in-law which releases him from marrying the widow. In reward for saying: “Nor a shoe-latchet,” I will issue your sons the decree to eat the paschal lamb, of which it is written: And thus shall ye eat it; with your loins girded, your shoes on your feet … it is the Lord’s passover (Exod. 12:11). Furthermore, I will exact retribution from Esau through it, as it is said: Upon Edom do I cast my shoe (Ps. 60:10). Likewise, I shall praise your children with that word, as it is said: How beautiful are thy steps in shoes (Song 7:2). Since you rejected the reward sought by ordinary men, your reward shall be multiplied in this world and in the world-to-come.

... “Moab is my washbasin…” (Tehillim 60:10) When Israel entered into their land in order to inherit it, the Holy One forbid them to conquer these three nations, as it says “Do not distress the Moabites…” (Devarim 2:9) So too regarding Edom it is written “You shall not provoke them…” (Devarim 2:5) From where do we learn that they were not to conquer the land of the Pelishtim? Because it is written “God did not lead them [by] way of the land of the Philistines for it was near…” (Shemot 12:17) The oath which Avraham swore to Avimelech was still near in time, “And now, swear to me here by God, that you will not lie to me or to my son or to my grandson…” (Bereshit 21:23) His grandson was still alive. In the future the Holy One will permit Israel to conquer all three, as it says “And they shall fly of one accord against the Philistines in the west, together they shall plunder the children of the East; upon Edom and Moab shall they stretch forth their hand, and the children of Ammon shall obey them.” (Yeshayahu 11:14) And it is translated as ‘they will join shoulder to shoulder as one to wipe out the Phillistines.’ Therefore it says “…Philistia, join me…” (Tehillim 60:10), Edom and Moav are their occupation as it says “Moab is my washbasin; on Edom I will throw my lock…” (ibid.)