Ali bin Abu Talib reported,

The Messenger of Allah ﷺ said, "The best thing that I and the prophets before me have said on the evening of Arafah is, 'There is no god but Allah alone, with no partner. To Him belongs the dominion and to Him belongs all praise, and He has power over all things.'"

Azami 11132

Hasan

عن علي بن أبي طالب قال

قال رسول الله ﷺ: أفضل ما قلت أنا والنبيون قبلي عشية عرفة: لا إله إلا الله وحده لا شريك له، له الملك وله الحمد وهو على كل شيء قدير.

الأعظمي 11132حسن
Contents
Reference
Commentary
Ayat
Collection
Jami al-Kamil
Book
Supplications, remembrances, and prayer upon the chosen Prophet ﷺ
Chapter
Supplications related to zakat, fasting, Hajj, slaughter, hunting, and transactions
Section
Best supplication is the supplication on the day of Arafah
Numbering
Jami al-Kamil 11132 (2nd edition)
Azami 11132