أَعْطَىٰ كُلَّ شَيْءٍ خَلْقَهُ ثُمَّ هَدَىٰ (who gave everything its shape then guidance 20:50) refers to the guidance of Takwin (تکوینی ھدایت).
Sayyidna Musa (علیہ السلام) reminded the Pharaoh, at the first place, of those acts of Allah Ta` ala which are obviously done by Him alone and about which no one else could claim that he has performed them. The Pharaoh totally unable to refute this argument, and in his confusion asked Sayyidna Musa (علیہ السلام) a question which was designed to entangle him into giving a reply that would greatly offend the Egyptians. The question was: how did the people of bygone ages stand who all worshipped idols, and what was their fate? The Pharaoh's purpose was that if Sayyidna Musa (علیہ السلام) replied (as the Pharaoh surmised he would) that they were all misguided and deserving of Hell, then he could instigate his people against the latter. But the reply which Sayyidna Musa (علیہ السلام) gave was so wise and discreet that the Pharaoh's evil design was completely frustrated.