‘Uthman bin Hakim says: I asked Sa‘id bin Jubayr about fasting in the month of Rajab, what is his opinion about it? He said: Sayyiduna ‘Abdullah bin ‘Abbas (may Allah be pleased with him) narrated to me that the Messenger of Allah (peace and blessings be upon him) would sometimes begin to fast so frequently that we would think he would not leave off fasting at all, but then he (peace and blessings be upon him) would leave off fasting for such a long period that we would think he would never fast again.
Hadith Referenceالفتح الربانی / كتاب الصيام / 3930
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«اخرجه البخاري: 1971، ومسلم: 1157، (انظر مسند أحمد ترقيم الرسالة: 3009 ترقیم بيت الأفكار الدولية: 3009»
Brief Explanation
Benefits: … Sa‘id ibn Jubayr intends to say that neither is fasting in Rajab prohibited, nor has any particular virtue or distinction been mentioned regarding it. From the practice of the Prophet (sallallahu alayhi wa sallam), it is understood that voluntary fasts (nafl) are not connected to any fixed or specified times; therefore, at times the Prophet (sallallahu alayhi wa sallam) would fast for several days, and at other times he would abandon this practice.