Musnad Ahmad 30:214

It was read to Sufyan: I heard Abu al-Zinad narrating from al-A'raj, from Abu Hurayrah, from the Prophet, peace and blessings of Allah be upon him: "If you say to your companion on the day of Friday while the Imam is delivering the sermon: 'Listen silently,' then you have engaged in idle talk." Sufyan said: Abu al-Zinad said: "It is Abu Hurayrah's own language."