It is narrated from Hazrat Abu Musa (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: The example of the knowledge and guidance with which Allah has sent me is like that of a heavy rain which falls upon the earth. Some land is pure and absorbs the water, and produces much grass and vegetation. And some land is hard and holds the water, by which Allah benefits the people; they drink from it and give others to drink. And some water falls on parts of the land which are barren plains; they neither retain the water nor produce any vegetation. This is the example of the one who gains understanding in the religion and benefits from what I have been sent with; he learns and teaches the knowledge of religion. And the example of the one who does not raise his head (i.e., does not pay attention) and does not accept the guidance with which I have been sent (i.e., no one benefits from him). In one narration, the words are: "And among them is a group that retains the water."