Sahih Muslim | Book 42 | Hadith Number 7143

Narrated by Hammam b. al-Harith
Hammam b. al-Harith reported that a person began to praise 'Uthman and Miqdad sat upon his knee; and he was a bulky person and began to throw pebbles upon his (flatterer's) face. Thereupon 'Uthman said: What is the matter with you? And he said: Verily, Allah's Messenger (may peace be upon him) said: When you see those who shower (undue) praise (upon others), throw dust upon their faces.