Lit. “To know; knowledge.” In Muslim theology, the word ‘Ilm is always used for religious knowledge. ‘Abdu ‘l-Haqq says it is the knowledge of religion as expressed in “the Book” (Qur’an) and the “Sunnah” (Traditions), and is of two kinds, ‘Ilmu ‘l-Mabadi, elementary knowledge, or that relating to the words and sentences of the Qur’an and Hadis; and ‘Ilmu ‘l-Maqasad, perfected knowledge, or that relating to faith and works, as taught in the Qur’an and Hadis. There is also ‘Ilmu ‘l-Mukashafah, revealed knowledge, or that secret knowledge, or light, which shines into the heart of the pious Muslim, whereby he becomes enlightened as to the truths of religion. This spiritual knowledge is also called ‘Ilmu ‘l-Haqiqah, or the knowledge of the truth. It is related (Mishkat, book ii. ch. i. Arabic ed.) that the Prophet said ‘Ilm is of three kinds, viz. Ayatu ‘l-Muhkam, Sunnatu ‘l-Qaim, and Farizatu ‘l-Adil, and that whatever is beyond these three is not necessary. The learned doctors explain these terms as follows: Ayatu ‘l-Muhkam, the established text of verses of the Qur’an; Sunnatu ‘l-Qa im, the correct Ahadis or Traditions; and Farizatu ‘l-Adi’, the lawful interpretation of the Qur’an and the Traditions.
The acquisition and the imparting of religious knowledge is very highly commended by Muhammad (see Mishkatu ‘l-Masabih, in loco.) –
“The desire of knowledge is a divine commandment for every Muslim, and to instruct in knowledge those who are unworthy or it is like putting pearls, jewels, and gold on the necks of swine.”
“Whoever is asked about the knowledge which he hath, and concealeth it, will be reined with a bridle of fire on the Day of Resurrection.”
“There are two avaricious persons that are never satisfied: one of them in knowledge, the more he attains the more he desires; the other of the world, with the things of which he is never satisfied.”
“That person who will pursue the road of knowledge, God will direct him to the road of Paradise; and verily the angels spread their arms to receive him that seeketh after knowledge, and everything in heaven and earth will ask grace for him. Verily the superiority of a learned man over a worshiper is like that of the full moon over all the stars.”
Based on Hughes, Dictionary of Islam