Musannaf Ibn Abi Shayba 2:249

Abu Bakr narrated to us, he said: 'Abdah bin Sulayman narrated to us, from Sa'id, from Qatadah, that Uthman, when he heard the Mu'adhdhin, would say as he said during the Tashahhud and all of the Takbir. When he said, "Hayya 'ala al-salah" (Come to prayer), he would say, "Ma sha' Allah, wa la hawla wa la quwwata illa billah" (What Allah wills, and there is no power and no strength except by Allah). And when he said, "Qad qamat al-salah" (The prayer has been established), he would say, "Marhaban bil-qa'ilina 'adlan, wa bis-salati marhaban wa ahlan" (Welcome to those who speak justly, and welcome and greetings to the prayer), then he would rise for the prayer.