“I once asked him (the Imam) (a.s.), about a man who performs Salah (prayer) with a people who are in a place lower than his place in which he performs Salah (prayer). He (the Imam) said, ‘If the Imam is in a place which is higher than their place like a raised place, a platform, their Salah (prayer) is not permissible. He (the Imam) said, ‘It is not harmful if he is higher by one shibr (8 inches). Or it is more or less in a gully if the land is stretched, or there is a raised place, the Imam stands on a higher place, those behind him in a lower place and the land is extended, except that they are on a sloping place. 5 He (the narrator) has said that he (the Imam) was asked, ‘What happens if the Imam stands below the place where people behind him stand? 5 He (the Imam) said, ‘It is not harmful. 5 He (the Imam) said, ‘If a man is on the roof or so and the Imam is on a place below, it is permissible for one to perform Salah (prayer) behind him to follow his Salah (prayer) even if it is very high. 5”