اللَّهُمَّ بَيِّضْ وَجْهِي يَوْمَ تَبْيَضُّ وُجُوهٌ وَتَسْوَدُّ وُجُوهٌ
Allahumma bayyid wajhi yawma tabyadduwujuhun wa taswaddu wujuh
Ô Allah, illumine mon visage le Jour où des visages seront illuminés et d'autres assombris.
While washing the face during wudu
This dua asks Allah for salvation on the Day of Judgment.