The Messenger of Allah ﷺ said, "If you say to your companion, 'Be quiet,' on Friday while the imam is delivering the sermon, you have spoken in vain."
أن رسول الله ﷺ قال: إذا قلت لصاحبك: أنصت يوم الجمعة والإمام يخطب فقد لغوت.
Bukhari narrated it in the Book of Friday Prayer (934) and Muslim in the Book of Friday Prayer (851), both via Layth, from Aqeel, from Ibn Shihab, "Saeed bin Musayab informed me, from Abu Hurairah," and he related it.Malik narrated it in the Muwatta of Qanabi, from him, from Ibn Shihab, with the same chain, as Jawhari mentioned in Musnad Muwatta (134). From this route Abu Dawud also transmitted it (1112), as did Yahya bin Yahya Andalusi in his Muwatta, from Malik, from Abu Zinad, from Aaraj, from Abu Hurairah, with the wording, "If you say to your companion, 'Be quiet,' while the imam is delivering the sermon on Friday, then you have committed laghw." Book of Friday Prayer (6).It is also found in Muslim (12/851) via Sufyan, from Abu Zinad, where the wording is, "faqad laghayta." Abu Zinad said, "That is Abu Hurairah's dialect. The correct form is, 'faqad laghawta.'"Suhayl bin Abu Salih also narrated it, from his father, from Abu Hurairah, from the Prophet ﷺ, with the wording, "If you speak on Friday while the imam is delivering the sermon, you have committed laghw," meaning while the imam is delivering the sermon. Ibn Khuzayma transmitted this (1804) via Muhammad bin Muamar Qaysi, who said, "Habban narrated to us, Wahib narrated to us, from Suhayl." Its chain is hasan, Qaysi is truthful, and likewise Suhayl bin Abu Salih.