Q579 :Rukn: the basic definition of
A579 : An action may be a rukn of an overall
obligatory action. When it is omitted, the whole action is rendered
invalid. We say, for example, that attendance at Arafat on the ninth
day of Thul-Hajjah is a rukn of pilgrimage. If a person does all the
other duties of pilgrimage without reaching Arafat before dawn of the
following day, which is the time limit for pilgrimage attendance, he
has not met this rukn and, therefore, he has not offered the
pilgrimage.
Our Dialogue ( Source : Arab News – Jeddah )