لَا إِلَهَ إِلَّا اللهُ ، وَحْدَهُ لَا شَرِيكَ لَهُ ، لَهُ الْمُلْكُ وَلَهُ الْحَمْدُ ، وهُوَ عَلَى كُلِّ شَيْءٍ قَدِيرٌ
Translation 
The best of supplications is the supplication on the day of AAarafah and the best which I and the Prophets before me have said (is):
“None has the right to be worshipped except Allah, alone, without partner. To Him belongs sovereignty and all praise and He is over all things omnipotent.”
“None has the right to be worshipped except Allah, alone, without partner. To Him belongs sovereignty and all praise and He is over all things omnipotent.”
Transliteration
laa ilaaha ill-allaahu, waḥdahu laa shareeka lah, lahul-mulku wa lahul-ḥamdu, wa huwa ‛alaa kulli shay’in qadeer
Sources:
At-Tirmithi No# 3585
