It has been narrated (through a still difterent chain of transmitters) by Anas that the Companions of Muhammad (ﷺ) were chanting on the day of the Battle of the Ditch
We are those who have sworn allegiance to Muhammad (And made a covenant with him) to follow Islam as long as we live. Hammad is not sure whether Anas said:" Ala'l-Islam" or," Ala'l-Jihad". And the Prophet (ﷺ) was chanting: O God, the real good is the good of the Hereafter, So forgive Thou the Ansar and the Muhajirs.