From Sahih Muslim (Hadith 4634):
It has been narrated on the authority of Shaqiq who said:I heard Sahl b. Hunaif say at Siffin: O ye people, find fault with your (own) discretion. By Allah, on the Day of Abu Jandal (i. e. the day of Hudaibiya), I thought to myself that, if I could, I would reverse the order of the Messenger of Allah (ﷺ) (the terms of the truce being unpalatable). By Allah, we have never hung our swords on our shoulders in any situation whatsoever except when they made easy for us to realise the goal envisaged by us, but this battle of yours (seems to be an exception). Ibn Numair (in his version) did not mention the words:" In any situation whatsoever
Reference: Muslim 4634