Musnad Abu Ya'la al-Mawsili 3:143

Ubayd Allah ibn Umar narrated to us, Abd al-Rahman narrated to us, from Sufyan, from Abu Ishaq, from Hani ibn Hani, from Ali, who said: Ammar came seeking permission to enter upon the Prophet, may Allah bless him and grant him peace. He said: "Give him permission. Welcome to the pure, the purified."