Why pharaoh`s [phiraeoon] is saved from thousands of year?

فَالْيَوْمَ نُنَجِّيْكَ بِبَدَنِكَ لِتَكُوْنَ لِمَنْ خَلْفَكَ اٰيَةً

And we let the children of Isra‘IL cross the sea. So, Pharaoh and his troops chased them in transgression and hostility, until when he was about to drown, he said, I believe that there is no god but the One in whom the children of Isra‘il believe, and I am among those who submit to Allah. [1]

(Allah said) Now (you believe) while you refused to believe before and you were one of the Mufsidn (evil-doers, corrupts, etc.).[2]

So this day we shall deliver your (dead) body (out from the sea) that you may be a sign to those who come after you! And verily, many among mankind are neglectful of Our Ayt (proofs, evidences, verses, lessons, signs, revelations, etc. [3]

Allah Almighty has saved his body because to show how wrong people are treated if we don`t fallow Quran and correct Hadith we will be treated like him. And his body is presently in the museum of Egypt.

This is one proof among billions.

1 Al-Quran 10:90

2 Al-Quran 10:91

3 Al-Quran 10:92