How sound is the saying that prayer in the mosque is an obligation upon every Muslim, and whoever does not perform his prayer with the congregation in the mosque is a disbeliever, and what are the legitimate excuses that permit absence from congregational prayer?

Scholars have differed concerning the ruling on congregational prayer. The preponderant opinion is that it is obligatory, but it does not have to be performed in the mosque. So, if they pray in congregation outside the mosque, they have fulfilled the obligation. It is, however, better to pray in the mosque. The saying that whoever does not perform the prayer with the congregation in the mosque is an infidel is incorrect. There are many excuses for not attending congregational prayer, among them: fear, rain, illness, repelling the two impurities (feces and urine), the presence of food one desires, eating something with a foul odor, and a guard who fears damage to what he was hired to guard.