Whoever wants to pray in a mosque in congregation has to go to the mosque, because if he follows the imam in his home this is not prayer in congregation, even if he can see the imam and congregation. Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) has spoken in detail on this issue.
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said in his commentary on Zaad al-Mustaqni’:
The phrase “and the same applies if he is outside and sees the imam or the congregation” means that a person’s following the imam is valid if he is outside the mosque, on condition that he can see the imam or the congregation. The apparent meaning of the author’s words is that it is not conditional upon the rows (of worshippers) being uninterrupted. So if it is assumed that a person is a neighbour of the mosque and he can see the imam or the congregation from his window and he prays in his house, and there is someone with him so that he is not praying alone, then it is valid for him to follow this imam, because he can hear the takbeer and see the imam or the congregation.
The apparent meaning of the author’s words is that he has to see the imam or congregation throughout the entire prayer, so that he will not miss following the imam. The view of our madhhab is that it is sufficient for him to see them for part of the prayer.
So, if he is outside the mosque, two conditions must be met:
1 – That he can hear the takbeer
2 – That he can see the imam or the congregation, either throughout the entire prayer, according to the apparent meaning of the author’s words, or for part of the prayer, according to the view of our madhhab.
The apparent meaning of his words is that it is not essential for the rows (of worshippers) to be uninterrupted, if the person is praying outside the mosque. This is the view of our madhhab.
The second view – which is that of the author of al-Muqni’, is that the rows (of worshippers) must be uninterrupted, and that it is not valid for one who is outside the mosque to follow the imam unless the rows are joined to one another, because what counts in congregational prayer is for all the worshippers to be doing the same things at the same time, following one imam in one place. But we say that if the imam and the worshippers are in the same mosque, and there are two other worshippers in another room between which and the mosque there is some distance, and another two in a third room, undoubtedly this is splitting up the congregation, especially according to the view of those who say that prayer in congregation must be offered in the mosque.
The correct view with regard to this matter is that it is essential for those who follow the imam from outside the mosque there should be no interruption in the rows; if there is any interruption in the rows then their prayer is not valid.
For example: there are buildings around the Haram, in which are apartments in which people pray. Those people can see the imam or the congregation for all or part of the prayer. According to the words of this author, their prayer is valid, but we say to them: if you hear the iqaamah then you can stay where you are and pray with the imam, and not come to al-Masjid al-Haraam.
According to the second opinion, the prayer is not valid, because the rows are interrupted. This is the correct view, which refutes the fatwa that stated by some contemporary scholars, that it is permissible to follow the imam in a prayer that is being broadcast. He wrote an essay concerning that, entitled al-Iqnaa’ bi Sihhat Salaat al-Ma’moom khalfa al-midhaa’. This view implies that we need not pray Jumu’ah in the Friday mosques, rather we can follow the imam of al-Masjid al-Haraam, because in that way we will have a larger congregation and that will be better, even though the one who follows a prayer broadcast on the radio cannot see the congregation or the imam, and if it comes by TV which broadcasts the prayer live, it is more likely to be appropriate.
But this is undoubtedly a false view, because it leads to abolishing of prayer in congregation and Jumu’ah prayer, and the rows (of worshippers) are interrupted in this case, and it does not achieve the purpose for which the Lawgiver enjoined prayer in congregation and Jumu’ah prayer.
The one who follows a broadcast prayer is not praying behind an imam who is in front of him, rather there is a huge distance between them, and this opens the door to evil, because the one who is careless about Jumu’ah prayer could then say that so long as it is valid to follow a prayer broadcast on the radio or TV, then I am going to pray at home, with my son or brother etc, and we will form a row.
But the correct view is that it is not valid to follow the prayer outside the mosque unless the rows are uninterrupted, and two conditions must be met:
1-That the worshipper can hear the takbeer
2-That the rows be uninterrupted.
With regard to seeing the imam or congregation, this is a matter that is subject to scholarly debate. But so long as the takbeer can be heard and the rows are uninterrupted, then it is valid to follow the imam. Based on this, if the mosque is full and the rows are uninterrupted, and people pray in the market places and outside shops, there is nothing wrong with that.
Al-Sharh al-Mumti’, 4/297-300.
And Allaah knows best.