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 heedless of Our Ayat (proofs, evidences, verses, lessons, signs , revelations, etc.). (Qur'an Surah Yunus 10:92)
Ibn Kathir Tafsir:
(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!) Ibn `Abbas and others from among the Salaf have said: "Some of the Children of Israel doubted the death of Fir`awn so Allah commanded the sea to throw his body -- whole, without a soul -- with his known armor plate. The body was thrown to a high place on the land so that the Children of Israel could confirm his death and destruction.'' That is why Allah said,
[فَالْيَوْمَ نُنَجِّيكَ]
("So this day We shall deliver your..'') meaning that We will put your body on a high place on the earth. Mujahid said,
(that you may be a sign to those who come after you!) meaning, so that might be a proof of your death and destruction for the Children of Israel. That also stood as a proof that Allah is All-Powerful, in Whose control are all the creatures. Nothing can bear His anger. Fir`awn and his people were destroyed on the day of `Ashura', as recorded by Al-Bukhari, Ibn `Abbas said, "When the Prophet arrived at Al-Madinah, the Jews fasted the day of `Ashura'. So he asked,
«مَا هَذَا الْيَومُ الَّذِي تَصُومُونَهُ؟»
(What is this day which you are fasting) They responded `This is the day in which Musa ( Moses ) was victorious over Fir`awn ( Pharoah ).' So the Prophet said,
«أَنْتُمْ أَحَقُّ بِمُوسَى مِنْهُمْ فَصُومُوه»
(You have more right to Moses than they, ( meaning, you follow Moses and believe in Moses and fear your Lord ) so you should fast on this day ( also ).
(93. And indeed We settled the Children of Israel in an honorable dwelling place, and provided them with good things, and they differed not until the knowledge came to them. Verily, your Lord will judge between them on the Day of Resurrection in that in which they used to differ.)