Riyad as-Salihin 162

Abu Musa (May Allah be pleased with him) reported: Messenger of Allah (ﷺ) said, "The similitude of guidance and knowledge with which Allah has sent me is like a rain which has fallen on some ground. A fertile part of earth has absorbed water and brought forth much grass and herbs. Another part, which is solid, held the water and Allah benefits men thereby, who drank and gave others to drink, and used it for irrigation. But some of it has fallen on a portion of sandy land which neither retains the water nor produces herbage. Such is the likeness of the man who understands the religion of Allah and who gets benefit of what Allah has sent me with; he learns and teaches others. It is also the likeness of the man who neither raises his head on that account (meaning he does not benefit from what the Prophet (ﷺ) was sent with) nor accepts Allah's Guidance with which I am sent". [Al-Bukhari and Muslim].