Sahih Muslim
The Book Pertaining to Piety and Softening of Hearts (Kitab Al-Zuhd wa Al-Raqaiq)
Book Number: 042 / Hadith Number: 7142
Abu Ma'mar reported that a person lauded a ruler amongst the rulers and Miqdad began to throw dust upon him and he said: Allah's Messenger (may peace be upon him) commanded us that we should throw dust upon the faces of those who shower too much praise.