It is reported from Hazrat ‘Abdullah bin ‘Abbaas (radhiyallahu ‘anhuma) that when Hazrat Abu Zar Ghifaari (radhiyallahu ‘anhu) learnt of the prophethood of Rasulullah (sallallahu ‘alaihi wasallam), he said to his brother, Hazrat Unais (radhiyallahu ‘anhu), “Go to Makkah Mukarramah and gather information about this man who claims that he is the messenger of Allah and that divine revelation descends upon him from the heavens. Also listen to his message.”