The Jumu`ah Prayer, in fact, enjoy particular privileges in Islam to the extent that a Surah of the Glorious Qur’an is named Surat Al-Jumu`ah. Muslims are commanded by Allah to forsake all worldly business at the time of the Jumu`ah and attend the Salah in the mosque. In this context, Allah, Most High, says, “O ye who believe! When the call is heard for the prayer of the day of congregation (Friday), haste unto remembrance of Allah and leave your trading. That is better for you if ye did but know. And when the prayer is ended, then disperse in the land and seek of Allah’s bounty, and remember Allah much, that ye may be successful. But when they spy some merchandise or pastime they break away to it and leave thee standing. Say: That which Allah hath is better than pastime and than merchandise, and Allah is the best of providers.” (Al-Jumu`ah: 9-11)
Keeping the above mentioned in mind, the Muslim should attend the Jumu`ah and attentively listen to the Khutbah (Friday sermon). Likewise, he should refrain form what interrupts the Khatib (Imam) or makes noise in the mosque.
For more elaboration on this vital question, we’d cite the following Fatwa issued by Sheikh M. S. Al-Munajjid, a prominent Saudi Islamic lecturer and author:
“First, speaking during the Khutbah when the Khatib is on the Minbar (pulpit) is Haram (unlawful) and the one who does that is committing a sin, even if he speaks words of Dhikr (remembrance of Allah) at this time.
Jumu`ah should be given due regard as the worshipper should be humble in body and soul and listen to the exhortation and knowledge which the general Muslim public needs to hear. It is not permissible to speak even if it is to enjoin what is good and forbid what is evil. Even though this (enjoining what is good and forbidding what is evil) is one of the most important duties of the Muslim, it is not allowed at this time (during the Khutbah) and one cannot even say “shush!” or “listen!” This is based on the following evidence:
It was reported from Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: “If you say to your companion ‘Listen!’ whilst the Imam is delivering sermon on Friday, you have spoken laghw (idle talk).” (Reported by Al-Bukhari and Muslim)
You see brother, may Allah bless you, even if you say to a person: “Listen!” – which is enjoining what is good and forbidding what is evil – Islam counts this as idle talk, which is forbidden at the time of Jumu`ah.
The matter is even more serious than that. Listen to the Hadith which comes next:
It was reported that Abu Ad-Darda’ said: “The Prophet (peace and blessings be upon him) sat on the Minbar and addressed the people, and recited an Ayah
 (Qur’anic verse). Ubayy ibn Ka`b was beside me and I said to him, ‘O Ubayy, when was this Ayah revealed?’ He refused to answer me. I asked him again and he ignored me, and I asked him again and he still ignored me, refusing to speak to me until the Messenger of Allah (peace and blessings be upon him) descended from the Minbar. Then Ubayy said to me, ‘All you got from your Jumu`ah was speaking idle talk.’ When the Messenger of Allah (peace and blessings be upon him) left, I went to him and told him what had happened. He said, ‘Ubayy spoke the truth. If you hear your Imam speaking, then listen to him until he finishes.’” (Reported by ibn Majah)
So, if inquiring about an Ayah during the delivery of the Khutbah deprives one of the reward of the Jumu`ah, so how about people who speak about their business or crops or other worldly matters? Another kind of negligence on some people’s part is when they make the Khutbah a time for taking a nap and cannot enjoy their sleep except during the time of the Jumu`ah.
Even saying “Yarhamuk Allah” (may Allah have mercy on you) to someone who sneezes, or returning Salams during the time of the Jumu`ah is not permitted. Al-Nawawi says in Al-Majmu`:
“The Sahih (authentic religious) texts forbid saying ‘Yarhamuk Allah’ to someone who sneezes and returning Salams.” (Tamam Al-Minnah, p. 335).
The same applies to all Adhkar such as Istighfar (seeking forgiveness from Allah) or Tasbih (glorification of Allah) etc. It is not permissible to say them aloud even though this is a Dhikr. The Khutbah is a kind of Dhikr because Allah says:
“O ye who believe! When the call is heard for the prayer of the day of congregation (Friday), haste unto remembrance of Allah and leave your trading. That is better for you if ye did but know.” (Al-Jumu`ah: 9)
This includes the Khutbah and the Prayer; both of them are remembrance of Allah. Other kinds of Dhikr such as Tasbih etc., are Sunnah and may be done at all other times; the Khutbah and listening to it, on the other hand, form an obligatory (Wajib) form of Dhikr which is prescribed for a short and specific time, during which focusing on the Khutbah takes precedence over focusing on any other kind of good deed or worship.
Similarly, saying “Ameen” to the Imam’s Du`aa’ and sending blessings on the Prophet (peace and blessings be upon him) if he is mentioned during the Khutbah, should be done silently by the members of the congregation, not aloud.
Secondly, the ban on speaking and making Dhikr applies whilst the Khatib is actually delivering the sermon on the Minbar. If he is on the Minbar but has not yet started delivering sermon, then there is no prohibition therein for speaking and remembering Allah, because it is said in the Hadith quoted above, “… whilst the Imam is delivering sermon on Friday…”
So, the ban on speaking is confined to the time when the Imam is actually delivering the Khutbah.
Concerning the Hadith, “When the Khatib ascends the Minbar, there should be no prayer and no speaking”, this is a false Hadith with no basis. (Al-Silsilat Ad-Da`ifah, p. 87)
Thirdly, there some occasions when it is permitted to speak or to move whilst the Khatib is speaking from the Minbar as follows:
If a person is faced with some need which he cannot put off dealing with, such as drowsiness, the need to relieve himself, or pain which means he has to move. The evidence for that is the Hadith: “If any one of you become drowsy in the mosque on the day of Jumu`ah, let him move from where he is to another spot.” (Reported by Abu Dawud) Al-Bayhaqi added the phrase “and whilst the Imam is delivering the Khutbah”. This was also classified as Sahih by Al-Albani.
It is permissible to do things which are permitted even during the Prayer, such as guiding a blind person so that he does not fall; or paying attention to the necessities of life in matters which may lead to death or may affect the common good such as the worshippers asking the Imam to pray for rain for them. It was reported that Anas ibn Malik said that a man entered the mosque on the day of Jumu`ah from the direction of the courtyard whilst the Messenger of Allah (peace and blessings be upon him) was standing and delivering the Khutbah. He turned to the Messenger of Allah (peace and blessings be upon him) and said, “O Messenger of Allah, our wealth (livestock) has been destroyed and our means of transportation (camels) has been cut off; implore Allah to help us.” So, the Messenger of Allah (peace and blessings be upon him) raised his hands… (Reported by Al-Bukhari)
It is permissible for a member of the congregation to co
rrect the Imam if he makes a mistake in an Ayah, or to prompt him if necessary, whilst he is standing on the Minbar. It is also permissible to refute the Khatib if he says something that amounts to polytheism, Bid`ah (innovation in religion), or Munkar (reprehensible error) during the Khutbah, so long as that will not lead to a greater evil happening in the mosque. If that is the case, then one should wait until after the Khutbah and then speak to the Imam, pointing out what is wrong. If the Imam speaks words of falsehood, it is not obligatory to listen to him. It was reported that some of the Salaf (early righteous Muslims) used to speak when the tyrant Al-Hajjaj was cursing `Ali ( may Allah be pleased with him) on the Minbar; they said, “We were not commanded to listen to this!”
It is permissible to pray Tahiyyat Al-Masjid (two Rak`ahs greeting the mosque); even if the Khatib is on the Minbar delivering the Khutbah. This is because of the Hadith of Jabir ibn `Abdullah who said that a man came whilst the Prophet (peace and blessings be upon him) was addressing the people on the day of Jumu`ah. He said, “Have you prayed, O so-and-so?” He said, “No.” he said, “Stand up and pray two Rak`ahs.” (Reported by Al-Bukhari)
If a person sees another person talking, it is not permissible to tell him to be quiet by speaking to him, as stated above, but one can indicate to him to be quiet by making a gesture, such as placing one’s finger on one’s lips.”