Jum’ah salah is fard-ayn. It has been established from the Qur’an, Hadith and the consensus of the ummah. It is one of the most salient features of Islam. The person who rejects Jum’ah salah is a kafir. The one who misses it without any valid excuse is a fasiq.
1. Allah says in the Quran:
"O you who believe! When the call for Jum’ah salah is made, hasten towards the remembrance of Allah and leave all transactions. This is best for you if only you know."
In this verse, "remembrance" refers to the Jum’ah salah and the khutbah.
2. The Prophet Muhammad (peace be upon him) said: "The person who has a bath on Friday, purifies himself as far as possible, applies oil to his hair, applies perfume, leaves for the masjid, amd when he arrives at the masjid he does not shove anyone from his place, offers as many nafl salahs as possible, and when the imam delivers the khutbah he remains silent - then his sins from the previous Jum’ah till then will be forgiven."
3. The Prophet Muhammad (peace be upon him) said: "The person who has a bath on Friday and goes early to the masjid on foot, and not by a vehicle, listens to the khutbah and does not do any foolish act while it is being delivered, will get the reward of one year's ibadah, one year's fasting, and one year's salah for every step that he takes."
4. The Prophet Muhammad (peace be upon him) said: “People should not leave out Jum’ah salah. If so, Allah will put a seal over their hearts whereby they will fall into severe negligence."
5. The Prophet Muhammad (peace be upon him) said: "The person who misses out three Jum’ah's without any valid reason, Allah puts a seal over his heart."
6. The Prophet Muhammad (peace be upon him) said: "The Jum’ah salah with jama'ah is a duty which is wajib on every Muslim with the exception of the following four persons: (i) a slave, (ii) a woman, (iii) an immature boy, (iv) a sick person."
7. The Prophet Muhammad (peace be upon him) said the following in regard to those who leave out Jum’ah: "It is my earnest desire that I appoint someone as imam in my place while I go and burn the homes of those who do not attend the Jum’ah salah." A similar Hadith has also been related with regard to leaving out salah in jama’ah.
8. The Prophet Muhammad (peace be upon him) said: "The person who leaves out Jum’ah salah without a valid reason is written down as a hypocrite in a book that is absolutely protected from any changes and modifications." In other words, he will be labelled as a hypocrite forever. However, if he repents or Allah forgives him solely out of His mercy, then this is another matter.
9. The Prophet Muhammad (peace be upon him) said: "Jum’ah salah becomes obligatory on the person who believes in Allah and the last day, except for the sick, musafir, woman, child, and a slave. If a person occupies himself in something unnecessary, or in some transaction and so neglects jum’ah salah, Allah also turns away from him and does not care about him and Allah is worthy of all praise."
10. Ibn Abbas (may Allah be pleased with him) says that the person who leaves out several Jum’ah salahs consecutively has in fact turned away from Islam.
11. A person asked Ibn Abbas regarding a person who passed away and did not join the Jum’ah and jama'ah salahs: "What do you have to say regarding such a person?" He replied: "That person is in jahannam."
Even by merely glancing at these Ahadith, one can come to the conclusion that the Shari’ah has laid great stress on Jum’ah salah and that severe warnings have been given to the one who leaves out Jum’ah.