Reference: al-Akhlaaq was-Siyar – Ibn Hazam al-Andalusee
Ibn Hazam al-Andalusee (rahima-hullaah) mentions:
A man who is a miser with his knowledge is worse than a man who is a miser with his money, for the money-miser is afraid of using up what he possesses but the knowledge-miser is being mean with something which does not get used up and is not lost when it is given away.
