Musnad Ahmad 648:11

Ya'qub narrated to us, my father narrated to us, from Muhammad ibn Ishaq, Muhammad ibn Ibrahim ibn al-Harith al-Taymi narrated to me, from 'Umar ibn al-Hakam ibn Thawban, from Ibn Las al-Khuza'i, who said: "Ammar ibn Yasir entered the mosque and performed two rak'ahs in it, making them light and complete. He said: Then he sat, so we stood up to him and sat beside him. Then we said to him: 'You have made these two rak'ahs of yours very light, O Abu al-Yaqzan.' He said: 'I hastened through them to prevent Satan from entering upon me during them.'" He said: Then he mentioned the rest of the hadith.