What is Hashem telling Pharaoh here?
Rashi and Targum Yonasan: He is informing Pharaoh that (he was lucky to be alive, because) He really ought to have killed him and his servants 1 during the plague of pestilence! And if He didn't, 2 it was in order to show him His strong Hand, and so that he would spread Hashem's Name throughout the land.
QUESTIONS ON RASHI
Rashi writes: "For even now, I dispatched My hand ... - For if I wanted to, ... I could have sent [the Dever] to strike you and your nation along with the animals...." Why explain this way?
Gur Aryeh: The verse cannot be understood literally. If Pharaoh is still here, obviously he was not stricken along with the animals by Dever!
Rashi writes: "If I wanted to, ... I could have... stricken you and your nation along with the animals...." Why explain this way?
Gur Aryeh: Hashem is always capable of punishing those whom He wishes, with or without a plague! Hashem explained to Pharaoh why He didn't strike the people and the animals with one plague of Dever, which would have saved the need for a separate Makah later. 1
As Gur Aryeh wrote above; refer to 9:14:1.1:2, and 9:14:1.2:1. Hashem did not do so, so as to increase the Makos and publicize His Name.