لَا إِلَٰهَ إِلَّا اللَّهُ وَحْدَهُ لَا شَرِيكَ لَهُ، لَهُ الْمُلْكُ وَلَهُ الْحَمْدُ وَهُوَ عَلَى كُلِّ شَيْءٍ قَدِيرٌ
The Prophet (peace be upon him) said: 'The best supplication is the supplication on the Day of Arafah, and the best of what I and the Prophets before me have said is: La ilaha illallahu wahdahu la sharika lah, lahul-mulku wa lahul-hamdu wa huwa 'ala kulli shay'in qadir.'