Musannaf Ibn Abi Shaybah 5280 — Those who used to say: when the imam

Tha'labah bin Abi Malik al-Qurazi said: I lived in the time of Sayyiduna Umar (may Allah be pleased with him) and Sayyiduna Uthman (may Allah be pleased with him). Our practice in their time was that when the imam came out for Jumu'ah, we would stop praying.