The ruling on the ma'mum praying outside the mosque while hearing the imam's voice

Question:
Is it valid for the ma'mum to pray outside the mosque while he hears the imam's voice, as the worshippers in this mosque do in the Friday prayer?

Answer:
If they can see the imam or the ma'mum through a door opening or a window, there is no harm. But if they cannot see anyone, neither the imam nor the ma'mum, and they are outside the mosque, it is not permissible. It is not permissible. Even if they hear the voice, they should go to another mosque. They should go to another mosque, whatever the case. As for people crowding around a mosque and praying in the streets, and some mosques not being half full and having only a few people, this is not permissible. All the mosques that have empty space, they should pray in them.