بُلُوغُ الْمَرَامِ
Bulugh al-Maram 454
The Book of Prayer
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.
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].
Sunnah.com reference: Book 2, Hadith 374