It is apparent from the context of his words, 'Have you come to us to drive us out of our land by your magic?' that his heart was trembling with fear of what Moses, blessings and peace be upon him, had brought. This was due to his knowledge and certainty that he was upon the truth. He knew that if the rightful one wanted to command the mountains, they would obey, and that one like him would not be forsaken nor would his supporters be few. He was certainly overpowered in his kingdom. And his saying, 'by your magic,' is an excuse and a confusion. Otherwise, how could it be hidden from him that a magician cannot drive out a king like him from his land and overpower him in his kingdom by magic?