Rukn (pillar): what an act cannot exist without, as against the condition and the obligation; the pillars of worship and of contracts; and the kissing of the corners of the Ka'ba

الركن

Rukn in the lexicon is the strongest side and the great matter; technically it is what a thing cannot exist without, the part of its essence, as against the condition, which is outside the essence, and against the obligation. ^{1 2 3} A pilgrim who leaves a pillar of the pilgrimage does not complete his rite; one who leaves an obligation makes it good by a sacrifice, and the Hanafis and Hanbalis apply this to prayer. ^{3 4} The pillars of ablution, tayammum, prayer, fasting, i'tikaf and pilgrimage differ between the schools. ^{4 5 6} In contracts the majority hold that each has three pillars, the formula, the two parties and the object, while the Hanafis hold the formula alone; the lack of a pillar makes the contract void. ^{6 7 8 9} The sunna is to touch or kiss the Black Stone and the Yemeni corner, and to point to them from afar when crowded. ^{9 10 11 12}