﴿ فَلَمَّا جَآءَهُم مُّوسَىٰ بِـَٔايَٰتِنَا بَيِّنَٰتٍۢ قَالُوا۟ مَا هَٰذَآ إِلَّا سِحْرٌۭ مُّفْتَرًۭى وَمَا سَمِعْنَا بِهَٰذَا فِىٓ ءَابَآئِنَا ٱلْأَوَّلِينَ ﴾

“But as soon as Moses came unto them with Our clear messages [Pharaoh and his great ones] said: “All this is nothing but spellbinding eloquence devised [by man]: and never did we hear [the like of] this, [nor has it ever been heard of] in the time of our forebears of old!””

If an individual thinks highly of himself, and if someone of apparently ordinary status comes before him and voices outright criticism of him, he immediately flares up. He ridicules his critic and makes different types of derogatory statements with a view to undermining him. This is what Pharaoh did in the case of Moses.