Ibn `Umar used to say about the Ila (which Allah defined (in the Holy Book), "If the period of Ila expires, then the husband has either to retain his wife in a handsome manner or to divorce her as Allah has ordered."
Ibn ‘Umar (may Allah be pleased with him) said: "When the period of four months has passed, the husband should be put in prison so that he divorces his wife, but the divorce does not occur unless the husband himself declares it."