Narrated Ibn 'Abbas (RA):

Allah's Messenger (ﷺ) said: "Whoever speaks on Friday while the Imam is giving the Khutbah (religious talk), he is like a donkey which carries books; and he who tells him to be quiet has no Jumu'ah." [Reported by Ahmad with an acceptable chain of narrators].

وَعَنِ ابْنِ عَبَّاسٍ رَضِيَ اَللَّهُ عَنْهُمَا قَالَ: قَالَ رَسُولُ اَللَّهِ ‏- صلى الله عليه وسلم ‏-{ مَنْ تَكَلَّمَ يَوْمَ اَلْجُمُعَةِ وَالْإِمَامُ يَخْطُبُ فَهُوَ كَمَثَلِ اَلْحِمَارِ يَحْمِلُ أَسْفَارًا, وَاَلَّذِي يَقُولُ لَهُ: أَنْصِتْ, لَيْسَتْ لَهُ جُمُعَةٌ } رَوَاهُ أَحْمَدُ, بِإِسْنَادٍ لَا بَأْسَ بِهِ .‏ [1]‏ وَهُوَ يُفَسِّرُ.‏