It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "The example of the one who talks on Friday while the imam is delivering the sermon is like a donkey carrying books, and the one who says to him: 'Be quiet', there is no Friday prayer (with its full reward) for him either."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12510