Hadithcore
Sunan Abi Dawud, 4666
sahih· Al-Albani

Qais b. ‘Abbad said :

I said to ‘All (Allah be pleased with him) : Tell me about this march of yours. Is this an order that the Messenger of Allah (ﷺ) had given you, or is this your opinion that you have? He said: The Messenger of Allah (ﷺ) did not give me any order; but this is an opinion that I have.

حَدَّثَنَا إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ الْهُذَلِيُّ، حَدَّثَنَا ابْنُ عُلَيَّةَ، عَنْ يُونُسَ، عَنِ الْحَسَنِ، عَنْ قَيْسِ بْنِ عُبَادٍ، قَالَ قُلْتُ لِعَلِيٍّ رضى الله عنه أَخْبِرْنَا عَنْ مَسِيرِكَ هَذَا أَعَهْدٌ عَهِدَهُ إِلَيْكَ رَسُولُ اللَّهِ صلى الله عليه وسلم أَمْ رَأْىٌ رَأَيْتَهُ فَقَالَ مَا عَهِدَ إِلَىَّ رَسُولُ اللَّهِ صلى الله عليه وسلم بِشَىْءٍ وَلَكِنَّهُ رَأْىٌ رَأَيْتُهُ ‏.‏

References2 variants
In-Book Reference
Book 42, Hadith 71
English Reference
Book 41, Hadith 4649