﴿ ثُمَّ بَعَثْنَا مِنۢ بَعْدِهِم مُّوسَىٰ وَهَٰرُونَ إِلَىٰ فِرْعَوْنَ وَمَلَإِي۟هِۦ بِـَٔايَٰتِنَا فَٱسْتَكْبَرُوا۟ وَكَانُوا۟ قَوْمًۭا مُّجْرِمِينَ ﴾

“And after those [earlier prophets] We sent Moses and Aaron with Our messages unto Pharaoh and his great ones: but they gloried in their arrogance, for they were people lost in sin.”

Because of their arrogance, Pharaoh and the chiefs of his people did not accept the word of Moses and Aaron. They judged all matters by the standard of power and glory instead of seeing them in the light of reason. Due to this self-established standard, they considered themselves of a high status and Moses and Aaron of a lower status. This mentality prevented them from accepting the Truth as presented to them by Moses and Aaron whom they regarded as inferior persons.