(a) Al-Azraq bin Qays narrates: We were in al-Ahwaz (the settlements lying between Iran and Basrah), fighting the Kharijites, and I was sitting on the bank of a river. Meanwhile a man (Abu Barzah al-Aslami, may Allah be pleased with him) began to pray holding the reins of his horse in his hand. The horse began to pull him, and he began to follow it.
(b) Shu'bah said: That man was Abu Barzah al-Aslami (may Allah be pleased with him). Seeing this, one of the Kharijites began to say: O Allah, ruin this old man! When he (may Allah be pleased with him) finished the prayer, he said: I heard what you said. I have taken part in six, seven or eight military expeditions with the Messenger of Allah (peace and blessings be upon him), and I have seen the ease he (peace and blessings be upon him) used to show the people. I prefer to return with my horse rather than leave it to go wherever it wishes and afterwards suffer hardship.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 3437