Allaah (The Most High) said: [وَڪَذَٲلِكَ زُيِّنَ لِفِرۡعَوۡنَ سُوٓءُ عَمَلِهِ -Thus it was made fair-seeming, in Fir’aun’s (Pharaoh) eyes, the evil of his deeds]
Evil deeds were made fair seeming to him, so shaytaan did not cease to make it fair seeming to him, whilst he called to it and beautified it, until he saw it as something good. He called to it and debated (in a manner) like those upon truth, whilst he was from the greatest of the corrupters.
[وَصُدَّ عَنِ ٱلسَّبِيلِۚ -And he was hindered from the path] of truth, due to the falsehood that was made fair seeming to him. [وَمَا ڪَيۡدُ فِرۡعَوۡنَ – And the plot of Fir’aun (Pharaoh)]–the one who wanted to plot against the truth and give a false impression to the people that he was the one upon truth, and that Moosaa was upon falsehood—[ إِلَّا فِى تَبَابٍ – led to nothing but loss]; That is: (complete) loss and waste. It benefited him in nothing except wretchedness in this world and in the Hereafter.
[For further details, see Tayseer Al-Kareem Ar-Rahmaan Fee Tafseer Kalaam Al-Mannaan]