Génesis 17:13 Midrash: Midrash Aggadah, Devarim Rabbah, Shir HaShirim Rabbah & Esther Rabbah

Another thing in Bereshit. ב & ר the beginning of the word, י & ת the end of the word, and it is a word ברית (brit) i.e. covenant, And thanks to the Word and the Sabbath, the Holy One with His blessing created the world, and from whence was the Sabbath called a covenant, when it was said to their generations an eternal covenant (Exodus 15), and the word was also called a covenant, which was said to be a covenant in your flesh (Genesis 17:13), and it was also because of the Torah that the world was created, because it remained from the word of Genesis Black fire and it is fire, and there is no fire but the Torah, which is said to be from the right hand, the fire of religion to him (Deuteronomy 32:2).

“If a bird's nest will happen before you on the way, on any tree or on the ground, with fledglings or eggs, and the mother is crouching on the fledglings or on the eggs, you shall not take the mother with the offspring” (Deuteronomy 22:6).
You shall surely send away the mother, and then take the offspring for yourself, so that it will be good for you, and you will have length of days (Deuteronomy 22:7).
Ki Tetze.¹This is the Hebrew name of a section of the Torah. It is used here as a heading for the midrash on this section. “If a bird's nest will happen before you” – halakha: A baby who was born circumcised, what is the ruling, is it permitted to circumcise him?²The question is whether it is obligatory to draw blood from the place of circumcision. If it is not obligatory, it would be forbidden to do so, lest he be injured in the process. This is what the Sages taught: A baby who is born circumcised, one must draw covenantal blood from him, because of the covenant of Abraham. From where can you derive this from the Torah? It is as it is stated: “You shall surely circumcise [himol yimol] those born in your house, or those purchased with your money” (Genesis 17:13).³The double expression himol yimol could be interpreted as follows: Even if someone is already circumcised [at birth], circumcise him.
Another interpretation, himol yimol – read it only as two acts of circumcision, circumcision and peeling back.⁴After removing the foreskin, a membrane still remains, which must be peeled back. There are thus two steps that must be followed when performing a circumcision.
Rabbi Levi said: Himol yimol – from here we learn that the circumciser must himself be circumcised, as it is written: “Himol yimol.”⁵The double expression is interpreted to mean: The circumciser shall be circumcised. Rabbi Yudan ben Pazi said: What is written regarding Tzippora, Moses’s wife? “Then she said: A bridegroom of blood [because of circumcisions…]” (Exodus 4:26). “Because of circumcision” is not written here, but rather, “circumcisions” – from here we learn about circumcision and from here we learn about peeling back.
Why is a baby circumcised at eight days? It is because the Holy One blessed be He extended mercy towards him, to wait for him until he has his strength. Just as the mercy of the Holy One blessed be He extends towards people, so does His mercy extend over animals. From where is this derived? It is as it is stated: “From the eighth day on, [it shall be accepted as a fire offering to the Lord]” (Leviticus 22:27). Moreover, the Holy One blessed be He said: “It and its offspring you shall not slaughter on one day” (Leviticus 22:28). And just as the Holy One blessed be He extended mercy towards animals, so did He become filled with mercy towards the birds, as it is stated: “If a bird's nest will happen before you.”

“Until the day is great and the shadows flee, I will go to the mountain of myrrh and to the hill of frankincense” (Song of Songs 4:6).
“Until the day is great” – Rabbi Abbahu and Rabbi Levi: one said: When Abraham our patriarch circumcised himself, his sons, and the members of his household, he made a hill of their foreskins, and the sun shone upon it and they became infested with worms. Their scent ascended before the Holy One blessed be He like the fragrance of the incense of spices and like the fragrance of the handful of frankincense that is burned upon the fires.⁸⁷It was as pleasing to God as the scent of the incense and the frankincense burned together with a portion of the meal offering in the Temple. The Holy One blessed be He said: When this one’s descendants will commit sins and evil deeds, I will remember this scent and I will be filled with mercy toward them and I will transform the attribute of justice into the attribute of mercy. What is the reason? “I will go to the mountain of myrrh [and to the hill of frankincense].”
Rabbi Levi said: When Joshua circumcised the children of Israel, he made a hill of their foreskins, and the sun shone upon it and they became infested with worms. Their scent ascended before the Holy One blessed be He like the fragrance of the incense of the spices and like the fragrance of the handful of frankincense that is burned upon the fires. At that moment the Holy One blessed be He said: When the descendants of these will commit sins and evil deeds, I will remember this scent and I will be filled with mercy over them and I will transform the attribute of justice into the attribute of mercy. What is the reason? “I will go to the mountain of myrrh [and to the hill of frankincense].”
It is written: “On that very day, Abraham was circumcised” (Genesis 17:26). Rabbi Berekhya said: Had Abraham circumcised himself at night, his generation would have said: Had we seen him we would not have allowed him. Instead, “on that very day Abraham was circumcised” – anyone who is bothered by it, let him speak.
Rabbi Abbahu bar Kahana and Rabbi Levi:⁸⁸These Sages address the question of why the verse states that Abraham “was circumcised” rather than stating that he circumcised himself. Rabbi Abbahu said: He felt it and he suffered,⁸⁹The verse states that Abraham “was circumcised” in order to indicate that he suffered like anyone else who undergoes circumcision. so that the Holy One blessed be He would multiply his reward. It is written: “One born in your house or purchased with your money shall be circumcised [himol yimol]” (Genesis 17:13). The Holy One blessed be He said: Shall one impure come and tend to one who is pure; is that possible?⁹⁰Shall an uncircumcised person circumcise one who is in the process of purification? Rather, one who is circumcised [hamul] shall circumcise [yimol]. I am pure and Abraham is pure; it is appropriate for the pure to tend to the pure. Rabbi Avin said in the name of Rabbi Shimon: The Holy One blessed be He joined His right hand to Abraham’s and circumcised him, as it is stated: “You established the covenant with him” (Nehemiah 9:8).