מדרש אויף תהילים 110:4

“Lord God, You have begun to show Your servant Your greatness and Your mighty hand, for what god is in the heavens or on the earth who can act in accordance with Your actions and according to Your mighty deeds” (Deuteronomy 3:24).
“Lord God, You have begun” – what is “Lord God”? Rabbi Yehoshua ben Korḥa said: In two places, Moses likened himself to Abraham, but it was to no avail for him. How so? The Holy One blessed be He called to Abraham, and he said: “I am here,” as it is stated: “And said to him: Abraham; and he said: I am here” (Genesis 22:1). What is “I am here”? I am here for priesthood, I am here for kingship; and he merited priesthood and kingship. From where is it derived that he merited priesthood? As it is stated: “The Lord has taken an oath, and He will not renounce it; you are priest forever by My decree, like Malkitzedek” (Psalms 110:4).¹⁰Malkitzedek was a priest (see Genesis 14:18). He merited kingship, as it is stated: “To the valley of Shaveh, which is the valley of the king” (Genesis 14:17).¹¹The midrash understands this as an allusion to the fact that the kings of the region elected Abraham as their king (see Bereshit Rabba 42:5).
Moses, too, sought to do so, as it is stated: “He said: Moses, Moses; and he said: I am here” (Exodus 3:4). I am here for priesthood; I am here for kingship. The Holy One blessed be He said to him: “Do not glorify yourself before a king, and do not stand in the place of the great” (Proverbs 25:6). “Do not approach [tikrav] here [halom]” (Exodus 3:5). You have no involvement with the priesthood, as it is stated: “The stranger who approaches [hakarev] shall be put to death” (Numbers 3:10). You have no involvement with the kingship, as it is stated: “That You have brought me here [halom]” (II Samuel 7:18).¹²David used the term halom in reference to the kingship.
Abraham said: “Lord God, what will You give to me?” (Genesis 15:2). Rabbi Levi said: He said before Him: ‘Master of the universe, if through justice¹³The name “God” represents the attribute of justice. I deserve to have children, give them to me; if not, give them to me through mercy.¹⁴The name “the Lord” represents the attribute of mercy. The Holy One blessed be He said: ‘As you live, you deserve them’: “And, behold, the word of the Lord was to him…[one who will emerge from your loins, he will be your heir]” (Genesis 15:4). Moses, too, said so: “Lord God, You have begun” – if through justice I deserve to enter the Land of Israel, let me enter; if not, let me enter through mercy. The Holy One blessed be He said to him: “Do not glorify yourself before a king…” “As you will not cross this Jordan” (Deuteronomy 3:27) – when Moses saw how resolute the matters were, he began speaking harsh words.¹⁵He began praying in a more forceful manner, as the midrash will detail in the next section.

Noah handed on the tradition to Shem, and he was initiated in the principle of intercalation; he intercalated the years and he was called a priest, as it is said, "And Melchizedek king of Salem… was a priest of God Most High" (Gen. 14:18). Was Shem the son of Noah a priest? But because he was the first-born, and because he ministered to his God by day and by night, therefore was he called a priest. Shem delivered the tradition to Abraham; he was initiated in the principle of intercalation and he intercalated the year, and he (also) was called priest, as it is said, "The Lord hath sworn, and will not repent, Thou art a priest for ever after the order of Melchizedek" (Ps. 110:4). Whence do we know that Shem delivered the tradition to Abraham? Because it is said, "After the order of Melchizedek" (ibid.). Abraham delivered the tradition to Isaac, and he was initiated in the principle of intercalation, and he intercalated the year after the death of our father Abraham, as it is said, "And it came to pass after the death of Abraham, that God blessed Isaac his son" (Gen. 25:11), because he had been initiated in the principle of intercalation and had intercalated the year (therefore) He blessed him with the blessing of eternity. Isaac gave to Jacob all the blessings and delivered to him the principle of intercalation. When Jacob went out of the (Holy) Land, he attempted to intercalate the year outside the (Holy) Land. The Holy One, blessed be He, said to him: Jacob! Thou hast no authority to intercalate the year outside the land (of Israel); behold, Isaac thy father is in the (Holy) Land, he will intercalate the year, as it is said, "And God appeared unto Jacob again, || when he came from Paddan-Aram, and blessed him" (Gen. 35:9). Why "again"? Because the first time He was revealed to him, He prevented him from intercalating the year outside the (Holy) Land; but when he came to the (Holy) Land the Holy One, blessed be He, said to him: Jacob ! Arise, intercalate the year, as it is said, "And God appeared unto Jacob again,… and blessed him" (ibid.), because he was initiated in the principle of the intercalation, and He blessed him (with) the blessing of the world. Thus were the Israelites wont to intercalate the year in the (Holy) Land. When they were exiled to Babylon || they intercalated the year through those who were left in the (Holy) Land. When they were all exiled and there were not any (Jews) left in the (Holy) Land, they intercalated the year in Babylon. (When) Ezra and all the community with him went (to Palestine), Ezekiel wished to intercalate the year in Babylon; (then) the Holy One, blessed be He, said to him: Ezekiel ! Thou hast no authority to intercalate the year outside the Land; behold, Israel thy brethren, they will intercalate the year, as it is said, "Son of man, when the house of Israel dwell in their own land" (Ezek. 36:17). Hence (the Sages) have said, Even when the righteous and the wise are outside the Land, and the keeper of sheep and herds are in the Land, they do not intercalate the year except through the keeper of sheep and herds in the Land. Even when prophets are outside the Land and the ignorant are in the Land they do not intercalate the year except through the ignorant who are in the land (of Israel), as it is said, "Son of man, when the house of Israel dwell in their own land"(ibid.) it is their duty to intercalate the year.

Rav Huna bar Kapara said: Abraham our patriarch sat and expounded: Orla is stated regarding a tree and orla is stated regarding man.¹⁹The foreskin, which is removed during a circumcision, is also called orla. Just as orla that is stated regarding the tree is in the place where it produces fruit, so orla that is stated regarding man is in the place where he produces offspring. Rabbi Ḥanin ben Pazi said: Did Abraham already know a fortiori inferences and verbal analogies? Rather, He hinted it to him: “I will establish My covenant between Me and you [and will multiply you exceedingly]” (Genesis 17:2), [implying that it is in] the place from which he procreates.
Rabbi Yishmael taught: The Holy One blessed be He sought to have the priesthood emerge from Shem, as it is stated: “Malkitzedek king of Shalem [brought out bread and wine and he was a priest of God, the Most High]” (Genesis 14:18). When he gave precedence to the blessing of Abraham over the blessing of the Omnipresent,²⁰“And he blessed him and said: Blessed be Abram…and blessed be God, the most High…” (Genesis 14:19–20). Abraham said to him: ‘Does one give precedence to blessing the servant over blessing the master?’ The Holy One blessed be He removed it from him and gave it to Abraham, as it is stated: “The utterance of the Lord to my master” (Psalms 110:1) and it is written thereafter: “The Lord has taken an oath, and He will not renounce it; you are a priest forever by My decree [divrati], like Malkitzedek” (Psalms 110:4); due to the speech [diburo] of Malkitzedek. That is what is written: “Blessed is Abram to God, the Most High, master of heaven and earth” (Genesis 14:19).
Rabbi Yishmael and Rabbi Akiva, Rabbi Yishmael says: Abraham was a High Priest; that is what is written: “The Lord has taken an oath, and He will not renounce it; you are a priest forever”; and it is written: “You shall circumcise the flesh of your foreskin” (Genesis 17:11). From where would he circumcise? If he would circumcise from the ear, he would remain ineligible to sacrifice. If he would circumcise from the heart, he would remain ineligible to sacrifice. If he would circumcise from the mouth, he would remain ineligible to sacrifice. From where would he circumcise and be eligible to sacrifice? One must say this is a mitzva of [the tip of] the body.²¹It must be that it is the foreskin that is removed, after which the individual remains unblemished.
Rabbi Akiva says: There are four instances of orla. Orla is stated regarding the ear: “Their ear is obstructed [arela]” (Jeremiah 6:10); orla regarding the mouth, as it is stated: “I am one of obstructed lips [aral sefatayim]” (Exodus 6:30); it is stated regarding the heart, as it is stated: “The entire house of Israel is of uncircumcised heart [arlei lev]” (Jeremiah 9:25). And it is written: “Walk before Me and be perfect” (Genesis 17:1). Where should he circumcise? If he would circumcise from the ear he would not be perfect. If he would circumcise from the mouth he would not be perfect. Where could he circumcise and be perfect? One must say this is the male organ.
Nagda said: It is written: “And one who is eight days old [shall be circumcised]” (Genesis 17:12). From where should he be circumcised? If from the ear, he will not be able to hear. If from the mouth, he will not be able to speak. If from the heart, he will not be able to think. From where could he be circumcised and be able to hear, speak, and think? One must say this is the male organ. Rabbi Tanḥuma said: Nagda’s [reasoning] is the most logical.
“An uncircumcised male who will not circumcise [the flesh of his foreskin]” (Genesis 17:14); Rabbi Yudan in the name of Rabbi Yitzḥak, and Rabbi Berekhya in the name of Rabbi Yitzḥak, and they taught it in the name of Rabbi Yosei ben Ḥalafta: “An uncircumcised male” – is there an uncircumcised female? Rather, at the place that one sees him and knows whether he is male or female, that is where one circumcises him.