Musar sobre Êxodo 10:8

We can explain the plain meaning of these verses in the following manner. First, (10,8) Pharaoh enquired who the people that would actually participate in that service to G–d would be, i.e. מי ומי ההולכים? Moses replied: "We will go with our young ones and with our old ones; with our sons and with our daughters as well as with our sheep and with our cattle, we will go, because it is a festival to G–d for us." Why did Pharaoh repeat מי ומי? The word ומי seems superfluous! Why did Moses twice say נלך, "We shall go?" When Pharaoh denied this request in verse 11, why did he preface his words with לא כן "Not so"?