"And Moses heeded the voice of his father-in-law" (Exodus 18:24) - certainly. "And he did all that he said" - what his father-in-law said to him; these are the words of Rabbi Yehoshua. Rabbi Elazar of Modiin says: "And Moses heeded the voice of his father-in-law" - certainly; "and he did all that he said" - what the Omnipresent said.
Whose Voice Did Moses Truly Obey When He Heeded Jethro
Mekhilta DeRabbi Shimon Ben Yochai 18:23
וישמע משה לקול חתנו ודאי: ויעש כל אשר אמר. מה שאמר לו חמיו כך דברי ר' יהושע: ר' אלעזר המודעי אומר וישמע משה לקול חתנו ודאי: ויעש כל אשר אמר מה שאמר המקום: