It is narrated from Sayyiduna Jabir (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) would not engage in fighting during the sacred months, except in the case when the enemy attacked him. If such a situation arose, he (peace and blessings be upon him) would wait until the sacred month had passed.
Hadith Referenceالفتح الربانی / أهم أحداث السنة الثانية للهجرة / 10686
Hadith Gradingمحدثین:صحیح
Hadith Takhrij«اسناده صحيح علي شرط مسلم ، (انظر مسند أحمد ترقيم الرسالة: 14583 ترقیم بيت الأفكار الدولية: 14637»
Brief Explanation
Benefits: … The sacred months are four: Muharram, Rajab, Dhu al-Qa'dah, and Dhu al-Hijjah. Regarding matters of fighting and warfare, the etiquette of these four months is that the people of Islam should not initiate any fighting with anyone. However, if the enemy launches an attack, then in response, jihad will be undertaken against them.