Az yashir/Hallel Sources

Why is the Chag [Sukkot] different, that we say [Hallel] on each day, and why on Pesach do we not say [Hallel]? All days of the Chag [Sukkot] are separate in their sacrifices; [those] of Pesach are not separate in their sacrfices

(11) Who is like You, O LORD, among the celestials; Who is like You, majestic in holiness, Awesome in splendor, working wonders!

באלם means AMONGST THE MIGHTY, just as (Ezekiel 17:13) “and the mighty of (אילי) the land he took away”; (Psalms 22:20) “O, thou my strength (אילותי) hasten to my help”.

(Exodus 15:11) "Who is like You among the mighty": Once Israel saw that Pharaoh and his hosts were lost in the Red Sea, and the rule of Egypt had been abolished and idolatry had been castigated, they all opened their mouths and said "Who is like You among the mighty." And not only did Israel alone break out in song. But all the peoples — When they heard that Pharaoh and his hosts had been lost in the sea and their rule had been abolished, and their idolatry had been castigated — all of them rejected their idolatry and opened their mouths and said "Who is like you among the mighty, etc." And thus do you find to be the lot of idolatry — that the peoples of the world are destined to reject it, viz. (Jeremiah 16:19) "The L rd is my strength and my stronghold and my refuge on the day of affliction … (20) Can a man make gods for himself, etc.", (Isaiah 2:20) "On that day a man will throw away his false gods … (21) to enter the clefts of rocks (in fear of retribution), etc.", (Ibid. 18) "and the false gods will perish completely." Variantly: "Who is like You among the mighty, O L rd": Who is like You in the miracles and wonders that You wrought for us upon the sea, viz. (Psalms 106:22) "… awesome deeds upon the Red Sea" — (Ibid. 9) "He roared at the Red Sea and it dried up." Variantly: "Who is like You bailmim" ("among the mute"). You hear the defamation of Your children and You remain silent, viz. (Isaiah 42:14) "I have ever been silent; I have been still; I have restrained Myself. (But now) I will scream as a woman giving birth. I will throb and lust (to destroy all My foes) together." In the past I was silent and restrained. From now on I will scream. (Ibid. 15-16) "I will lay waste the mountains and the hills, and I will dry up all their grass, and I will render the rivers islands, and I will dry up the pools. And I shall lead the blind in a way they did not know. In roads they did not know shall I lead them. I shall make the darkness into light before them, and the crooked paths into straight paths." Variantly: "Who is like You among the mighty": Who is like You among those who minister before You on high, viz. (Psalms 89:7) "Who in the heavens can be likened to the L rd?" (Ibid. 8) "a G d who is dreaded in the great council of the holy ones (the angels) … (9) O L rd, G d of hosts, who is like You? Mighty is the L rd." Variantly: Who is like You ("ba'eilim") among those who call themselves gods? Pharaoh called himself a god, viz. (Ezekiel 29:3) "Mine is my river (the Nile), and I have made it." And thus, Sancherev, viz. (II Kings 18:35) "Who among all the gods of the lands (saved their land from my hand, etc.")? And thus Nevuchadnezzar, viz. (Isaiah 14:14) "I shall mount the heights of a cloud; I shall liken myself to the Most High!" And thus, Negid Tzor, viz. (Ezekiel 28:2-3) "Say to Negid Tzor: Because your heart has grown proud and you have said: I am a god, etc." Variantly: Who is like You among those whom others call "gods" and who are without substance, those of whom it is written (Psalms 115:5) "hey have a mouth but cannot speak, etc." But the Holy One Blessed be He says two things in one pronouncement, something that a man cannot do, viz. (Ibid. 62:12) "One (pronouncement) has G d spoken; these two (things) have I heard." (Jeremiah 23:29) "Is My word not like fire, says the L rd, and like a hammer shattering rock?" And it is written (Iyyov 37:2) "And a word shall come forth from His mouth, etc."

Among the mighty (eilim). This refers to the angels. By contrast, the term b’nei eilim—literally, “sons of the mighty” (Tehillim 29:1)—refers to the stars.