Sahih al-Bukhari 3181
Sahih al-Bukhari · Book 58: Jizyah and Mawaada'ah · Chapter 18
Narrated Al-A`mash:
حَدَّثَنَا عَبْدَانُ ، أَخْبَرَنَا أَبُو حَمْزَةَ ، قَالَ سَمِعْتُ الأَعْمَشَ ، قَالَ سَأَلْتُ أَبَا وَائِلٍ شَهِدْتَ صِفِّينَ قَالَ نَعَمْ، فَسَمِعْتُ سَهْلَ بْنَ حُنَيْفٍ ، يَقُولُ اتَّهِمُوا رَأْيَكُمْ، رَأَيْتُنِي يَوْمَ أَبِي جَنْدَلٍ وَلَوْ أَسْتَطِيعُ أَنْ أَرُدَّ، أَمْرَ النَّبِيِّ صلى الله عليه وسلم لَرَدَدْتُهُ، وَمَا وَضَعْنَا أَسْيَافَنَا عَلَى عَوَاتِقِنَا لأَمْرٍ يُفْظِعُنَا إِلاَّ أَسْهَلْنَ بِنَا إِلَى أَمْرٍ، نَعْرِفُهُ غَيْرِ أَمْرِنَا هَذَا.
I asked Abu Wail, "Did you take part in the battle of Siffin?" He said, 'Yes, and I heard Sahl bin Hunaif (when he was blamed for lack of zeal for fighting) saying, "You'd better blame your wrong opinions. I wish you had seen me on the day of Abu Jandal. If I had the courage to disobey the Prophet's orders, I would have done so. We had kept out swords on our necks and shoulders, for a thing which frightened us. And we did so, we found it easier for us, except in the case of the above battle (of ours).' "