and whoever says to him, “Pay attention,” has no Friday (reward); that is, he is deprived of its full reward.
In the Two Ṣaḥīḥs it is related from Abū Hurayrah: “If, on a Friday, you say to your companion, ‘Listen,’ while the imam is delivering the sermon, you have engaged in idle talk,” meaning you have uttered frivolity, and frivolity is sin. If even the person who tells the speaker to be quiet—although he is essentially commanding what is right—has lapsed into idle talk and been forbidden to do so, then any other speech is, a fortiori, even more objectionable.
It is permissible for the imam to address some of the congregants during the sermon, and it is likewise permissible for a congregant to speak to him when there is a genuine benefit, for the Prophet ﷺ spoke with a beggar and the beggar spoke to him. Similar incidents occurred several times when the Messenger of Allah ﷺ conversed with certain Companions—and they with him—during the sermon for a beneficial reason of instruction or need, and because such brief exchanges do not distract from listening to the sermon.
It is not permissible for someone who is listening to the sermon to give charity to the beggar during the sermon, because the beggar has done what he is not allowed to do; one must not assist him in what is unlawful—namely, speaking during the sermon.
Sending blessings upon the Prophet ﷺ is recommended when one hears them from the preacher, yet he should not raise his voice, lest he distract others.