The person who offers Salaat Ul ‘Isha congregationally has as if spent half the night in worship and whoever offers Salaat Ul Fajr also congregationally, that man has as if spent the whole night in worship. (Sahih Muslim, Hadith No. 656) ” If they knew the merits of Salajh after nightfall ( Isha ‘ ) and the morning ( Fajr ) Salat , they would come to them even if they had to crawl to do so . “