עִיכּוּבָא, indispensable condition. Yoma 5ᵃ bot. ככה ע׳ היא the emphatic expression ‘thus’ (Ex. XXIX, 35) intimates the indispensableness of any of the prescribed forms. Ib.ᵇ ושמרתם … ע׳ the emphatic expression, ‘and ye shall guard’ (Lev. VIII, 35) intimates &c.