Mujahid (may Allah have mercy on him), Ata (may Allah have mercy on him), al-Hasan (may Allah have mercy on him) and al-Dahhak (may Allah have mercy on him), all of these authorities say that the imam has been given the choice regarding the muharib (one who wages war).
Hadith Referenceمصنف ابن ابي شيبه / كتاب السير / 34996
Hadith Takhrij(مصنف ابن ابي شيبه: ترقيم سعد الشثري 34996، ترقيم محمد عوامة 33468)