It was narrated that 'Ali bin Abu Talib said:
"I was sitting with the Prophet, and 'Ammar bin Yasir asked permission to enter. The Prophet said: 'Let him in, welcome to the good and the purified.'" (FR)
English reference (FR): Vol. 1, Book 1, Hadith 146 (FR)
Arabic reference (FR): Book 1, Hadith 151 (FR)