I was wondering whether, before the first time Moshe went to Pharaoh, he knew that there would be 10 plagues, and what they would be.
Why does Hashem command Moshe to perform each macah (plague)? Hashem can perform the Macot himself (by sending malachim).
Why did Moshe and Aaron need to use a staff in initiating the plagues? Such as in שמות פרק ז פסוק יט: יט. וַיֹּאמֶר יְהֹוָה אֶל משֶׁה אֱמֹר אֶל אַהֲרֹן קַח מַטְּךָ וּנְטֵה יָדְךָ עַל מֵימֵי ...