Малик ибн Анас
Malik ibn Anas reported from Talha ibn Ubaydullah ibn Kariz that Muhammad said, "The best dua is dua on the day of Arafa, and the best thing that I and the Prophets before me have said is "There is nothing worshipped but Allah, alone without any partner" (La ilaha illa'llah, wahdahu la sharika lah)"