Ezekiel 29:3 Speak these words: Thus said the Sovereign GOD: I am going to deal with you, O Pharaoh king of Egypt, Mighty monster, sprawling in your channels, Who said, My Nile is my own; I made it [for] myself.
*Bereshit Rabbah 100:1 “Know that the Lord is God” (Psalms 100:3) – Rabbi Yehuda bar Simon and Rabbi Aḥa, Rabbi Yehuda bar Simon said: “Know that the Lord is God, He made us, and we did not [velo]” (Psalms 100:3) create ourselves, unlike Pharaoh, who said: “My river is mine and I made myself” (Ezekiel 29:3). Rabbi Aḥa said: “Know that the Lord is God, He made us and to Him [velo]” we devote ourselves.
Midrash Tanchuma Buber, Vaera 8:1 Another interpretation (of Exod. 7:1) SEE, I HAVE SET YOU AS A GOD TO PHARAOH. The Holy One said: Because he made himself into a god, they informed him that he was nothing in the world. See, I have made you a god over him. And where is it shown that Pharaoh made himself into a god? Where it is stated (of Pharaoh in Ezek. 29:3): {BECAUSE HE} [WHO] SAID {THE} [MY] NILE IS MY OWN, AND I MADE MYSELF. I am the one who created myself.*
Why did the midrash interpret the words of the pharaoh in the verse as "I made myself - created myself" instead of " I made it (the river) myself." ?