Abu Huraira (Allaah be pleased with him) reported: Allaah's Messenger (sallAllaahu alayhi wa sallam) addressed us and said: O people, Allaah has made Hajj obligatory for you; so perform Hajj. Thereupon a person said: Messenger of Allaah, (is it to be performed) every year? He (the Prophet) kept quiet, and he repeated (these words) thrice, whereupon Allaah's Messenger (sallAllaahu alayhi wa sallam) said: If I were to say" Yes," it would become obligatory (for you to perform it every year) and you would not be able to do it. Then he said: Leave me with what I have left to you, for those who were before you were desroyed because of excessive questioning, and their opposition to their Prophets. So when I command you to do anything, do it as much as it lies in your power and when I forbid you to do anything, then abandon it.