Follow religious rulings set by those in authority without making assumptions or acting on one's own judgement without consulting them first .

This hadith is about following the rulings set by Umar ibn al-Khattab, who was known as the Commander of Believers. The man in this hadith was advising Abu Musa Al-Ash'ari to be careful when issuing rulings concerning Tamattu', which is a type of pilgrimage to Mecca. He suggested that Abu Musa should not make any assumptions about what Umar has introduced into religious rites since he did not know for sure. When Abu Musa later met with Umar, he asked him why he did not allow people to lie with their wives in the shade of Arak trees before going out for Hajj with their heads dripping due to taking a bath after sexual relations. Umar explained that although this practice was done by Prophet Muhammad and his companions, he did not want people to do it because it would look inappropriate for them to go out for Hajj looking like that. This hadith teaches us that we should always follow religious rulings set by those in authority and never make assumptions or act on our own judgement without consulting them first.