Hadith 10:609
Abu Bakr narrated to us, he said: Hushaym narrated to us, from Mughira, from Ibrahim, who said: There is no time limit for *Zihar* (the pronouncement of a wife as being like one's mother), unless he says: "If I approach you." If he says that and then leaves her for four months, she becomes separated from him by *Ila* (the oath of abstention).
حدثنا أبو بكر قال نا هشيم عن مغيرة عن إبراهيم قال ليس في الظهار وقت إلا أن يقول إن قربتك فإن قال فتركها أربعة أشهر بانت منه بالإيلاء