Ibn ‘Abbas reported God’s Messenger as saying, “If any one hears him who makes the call to prayer and is not prevented from joining the congregation by any excuse,” (he was asked what an excuse consisted of and replied that it was fear or illness), “the prayer he says will not be accepted from him.”
Abud Darda’ reported God’s Messenger as saying, “If there are three men in a village or in the desert among whom prayer is not arranged, the devil has got the mastery over them. So observe prayer in company, for the wolf eats only the straggling animal.”
‘Abdallah b. Arqam said he heard God’s Messenger say, “When the time for prayer comes and one of you needs to relieve himself, he should do that first.”
Tirmidhi transmitted it, and Malik, Abu Dawud and Nasa’i transmitted something similar.
God’s Messenger led us in the dawn prayer one day, and when he gave the salutation he asked, “Is so and so present?” and was told that he was not. He asked, “Is so and so present?” and was told that he was not. He then said, “These two prayers* are the ones which are most burdensome to hypocrites. If you knew the blessings they contain you would come to them, even though you had to crawl on your knees. The first row is like that of the angels, and if you knew the nature of its excellence you would race to join it. A man’s prayer said along with another is purer than his prayer said alone, and his prayer with two men is purer than his prayer with one, but if there are more it is more pleasing to God.”
