Arabic
لاَ إِلَهَ إِلاَّ اللَّهُ وَحْدَهُ لاَ شَرِيكَ لَهُ لَهُ الْمُلْكُ وَلَهُ الْحَمْدُ وَهُوَ عَلَى كُلِّ شَيْءٍ قَدِيرٌ
Meaning
There is no deity but Allah, alone, without partner. His is the dominion and His is the praise, and He has power over all things. ("The best supplication is the supplication of the Day of Arafah.")
Source
HadithTirmidhi 3585