This work traces the spiritual and intellectual significance of fasting to its root meaning in Arabic as self-restraint (kaff or imsāk), around which revolve other related notions: that the intellect (ʿaql)—being the spiritual reality in man and endowed with the ability to think about consequences (tadabbur)—renders self-restraint possible; that self-restraint is often required in one’s search for nobler cause, including one’s quest for knowledge; that self-restraint as an act with no immediate observable form makes it so conducive for sincerity; and that in restraining himself from eating during fasting, man is actually emulating God’s Name, al-Ṣamad.