What is the ruling on one who swore to quit smoking, then returned to it after a period of weakness, and this recurred more than once; is he required to offer expiation for every time he smokes after his oath?

An answer has already been provided regarding the issue of swearing to quit smoking and the atonement required when oaths are repeatedly made concerning the same matter. One must beware of befriending those who aid in sin, and be keen to associate with people of goodness and righteousness.