Musnad Abu Ya'la al-Mawsili 243:90

And from Abu Musa, from the Prophet, may Allah bless him and grant him peace, who said: "The likeness of that which Allah has sent me with of guidance and knowledge is like rain that struck land. A portion of it was good, which accepted the water and produced much fodder and grass. Another portion of it was basins that held the water, so Allah benefited the people through it; they drank from it, gave drink, and cultivated. And another portion of it was struck, which was merely barren ground that neither holds water nor produces grass. That is the likeness of one who gains understanding in the religion of Allah and benefits from that which Allah sent me with, so he learns and teaches. And the likeness of one who does not raise his head for that, and does not accept the guidance of Allah with which I was sent."