Hazrat Abdullah bin Amr (radhiyallahu ‘anhuma) reports that Rasulullah (sallallahu ‘alaihi wasallam) would recite the following abundantly on the Day of Arafah:

لَا إِلٰهَ إِلَّا اللهُ وَحْدَهُ لَا شَرِيْكَ لَهُ لَهُ الْمُلْكُ وَلَهُ الْحَمْدُ بِيَدِهِ الْخَيْرُ وَهُوَ عَلٰى كُلِّ شَيْءٍ قَدِيْرٌ

There is no deity besides Allah Ta‘ala alone, who has no partner. To Him belongs the kingdom (of the entire universe), and only for Him belongs all praise. In His hand (control) alone lies all good and He alone has complete power over everything. (Musnad Ahmed #7080)