(Exodus 15:10) "in the mighty waters": Four are called "mighty": The Holy One Blessed be He — (Psalms 93:4) "Mighty on high is the L–rd"; Israel — (Ibid. 16:3) "the mighty, the object of all My desire"; Egypt — (Ezekiel 32:18) "and the daughters of the mighty nations (Egypt)"; and the waters — "They plummeted like lead in the mighty waters."
In the Mighty Waters Four Are Called
Mekhilta Tractate Shirah 7:11