Adhaan

Nabi ﷺ (peace and blessings be upon him) disliked using the methods of the Jews and Christians for calling the people to assemble at the time of Salaah. There was a need to adopt a method to gather the people in the Musjid at the time of Salaah. Allah ﷻ (exalted is His majesty) showed some of the Sahaabah رضي الله عنهم (may Allah be pleased with them) the adhaan in their dreams. The Sahaabah رضي الله عنهم (may Allah be pleased with them) related their dreams to Nabi ﷺ (peace and blessings be upon him) and he accepted the adhaan as the method of gathering people to the Musjid. It was then introduced and implemented in the shariah. Hadhrat Bilal رضي الله عنه (may Allah be pleased with him) was appointed as the muadh-dhin and Allah ﷻ (exalted is His majesty) made him the leader of the muadh-dhins till the Day of Qiyaamah.