Ājañña Jātaka (No.24)
Once, when Brahmadatta was ruling in Bārāṇasī, seven kings laid siege to the city. A warrior sent by Brahmadatta harnessed two horses (brothers) and, sallying forth from the city, overcame six camps and captured six kings. Just then the elder horse (who was the Bodhisatta) was wounded. The charioteer unfastened the horse’s armour as he lay on his side, and started to arm another horse. The Bodhisatta addressed the charioteer and said that as an Ājañña horse he must fight on. The charioteer set him on his feet again and, with his help, captured the seventh camp and its king.
The Bodhisatta, having counselled the victorious king to show mercy to his captives, died, and his body was burnt with all honours.
The story was told to a monk who had given up striving. J.i.181‑2.