La Genèse 16:7 Midrash : Mekhilta DeRabbi Yishmael, Bereshit Rabbah & Sifrei Devarim

וַֽיִּמְצָאָ֞הּ מַלְאַ֧ךְ יְהוָ֛ה עַל־עֵ֥ין הַמַּ֖יִם בַּמִּדְבָּ֑ר עַל־הָעַ֖יִן בְּדֶ֥רֶךְ שֽׁוּר׃

Un envoyé du Seigneur la trouva près d’une source d’eau, dans le désert, près de la source sur le chemin de Chour.

Mekhilta DeRabbi Yishmael

R. Nathan asked R. Shimon b. Yochai: In all places you find "the angel of the L–rd ("yod-keh-vav-keh") — (Genesis 16:7) "and an angel of the L–rd found her" — (Ibid. 9) "and the angel of the L–rd said to her" — (Exodus 3:2) "and an angel of the L–rd appeared to him" — And here it is written "and the angel of G–d (Elokim) turned." (Why is this so?) He answered: "elohim" in all places is a judge. We are hereby apprised that Israel were being judged at that time — whether to be rescued or to be destroyed with the Egyptians (for themselves having succumbed to idolatry.)

Bereshit Rabbah

“The angel of the Lord found her in the wilderness, at the spring of water on the road to Shur” (Genesis 16:7).
“The angel of the Lord found her…at the spring of water [on the road to Shur]…” – on the road to Ḥalutza.
“He said: Hagar, Sarai’s maidservant, from where did you come, and where are you going? She said: From my mistress Sarai I am fleeing” (Genesis 16:8).
“He said: Hagar, Sarai’s maidservant” – if one says to you: Your ears are like those of a donkey, pay him no mind; if two [people tell you this], make a bridle for yourself.32If one person points out a fault to you, pay him no heed. If two people tell you, realize that the critique is true. So, Abram said: “Behold, your maidservant is in your hand.” The angel said: “Hagar, Sarai’s maidservant.” So she said: “From my mistress Sarai I am fleeing.”33Both Abraham and the angel referred to her as a mere maidservant; as a result she regarded herself as a mere maidservant, by referring to Sarah as “my mistress.”
“The angel of the Lord said to her: Return to your mistress and suffer under her hands” (Genesis 16:9).
“The angel of the Lord said to her: I will multiply your descendants, and they shall not be counted due to their great number” (Genesis 16:10).

“The angel of the Lord said to her: Return to your mistress and suffer…The angel of the Lord said to her: I will multiply…” How many [different] angels encountered her? Rabbi Yosei bar Ḥanina said: Five – every time “saying” is stated, there was another angel.34The words: “The angel of the Lord found her” is also counted as a “saying.” The Rabbis say: Four – every time “angel” is stated [there was another angel].
Rabbi Ḥiyya said: Come and see how great the difference is between the earlier generations and the later generations. Manoaḥ said to his wife [upon seeing an angel]: “We will die because we have seen God” (Judges 13:22). But Hagar, Sarai’s maidservant, saw five angels one after the other and did not fear them. Rabbi Ḥiyya said: [Better] the fingernail of the forefathers and not the belly of the descendants.35The preceding generations are so much greater than their descendants that even the former’s fingernails are most substantial than the latter’s torso.
Rabbi Yitzḥak said: “She supervises [tzofiya] the proceedings of her household” (Proverbs 31:27)36This verse is expounded as a reference to Abraham and Sarah in the Midrash of Proverbs. – the members of Abraham’s household were prophets [tzofim], so she was accustomed to seeing them [angels].

Bereshit Rabbah

“Messengers [malakhim]” – these were flesh and blood messengers. The Rabbis say: Actual angels. Rabbi Ḥama bar Ḥanina said: Hagar was Sarah’s maidservant and five angels happened upon her,8See Genesis 16:7–12. this one who is the beloved of the household, all the more so. If several angels escorted Eliezer,9See Genesis 24:7 and Bereshit Rabba 59:10. who was a slave of the household, this one, who was the beloved of the household, all the more so. Rabbi Yosei said: Joseph was the youngest of the tribes and three angels escorted him; that is what is written: “A man found him”10Since the “man” is unidentified and appears by chance, and also plays a crucial role in the story, the midrash understands that the mysterious man was, in fact, an angel. (Genesis 37:15), “the man asked him” (Genesis 37:15), “the man said to him” (Genesis 37:17); this one, who was the father of them all, all the more so.
“Before him” – before the one whose time to assume kingship was before his.11See Genesis 36:31. Rabbi Yehoshua said: He removed his royal purple garment and cast it before him. He said to him: ‘Two starlings cannot sleep on one board.’12Our kingdoms cannot overlap.
“To Esau his brother” – although he is Esau, he is his brother.
“To the land of Se’ir, the field of Edom” – he is ruddy, his cooked food is red, his land is red, his mighty are red, his garment is red, and a red one will exact retribution from him in red garments. He is ruddy – “the first emerged ruddy” (Genesis 25:25); “his cooked food is red” – “feed me please from that red, red dish” (Genesis 25:30); “his land is red” – “to the land of Se’ir, the field of Edom”13Red, adom, is similar to Edom. See Genesis 25:30.; “his mighty are red” – “mighty ones are colored scarlet…” (Nahum 2:4); and a red [adom] one will exact retribution from him – “my beloved is clear and ruddy [adom]” (Song of Songs 5:10); in red garments – “why is there red on your garments?” (Isaiah 63:2).