حَدَّثَنِي أَبُو مَعْنٍ الرَّقَاشِيُّ، زَيْدُ بْنُ يَزِيدَ أَخْبَرَنَا عُمَرُ بْنُ يُونُسَ، حَدَّثَنَا عِكْرِمَةُ، - وَهُوَ ابْنُ عَمَّارٍ - قَالَ قَالَ إِسْحَاقُ قَالَ أَنَسٌ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم مِنْ أَحْسَنِ النَّاسِ خُلُقًا فَأَرْسَلَنِي يَوْمًا لِحَاجَةٍ فَقُلْتُ وَاللَّهِ لاَ أَذْهَبُ ‏.‏ وَفِي نَفْسِي أَنْ أَذْهَبَ لِمَا أَمَرَنِي بِهِ نَبِيُّ اللَّهِ صلى الله عليه وسلم فَخَرَجْتُ حَتَّى أَمُرَّ عَلَى صِبْيَانٍ وَهُمْ يَلْعَبُونَ فِي السُّوقِ فَإِذَا رَسُولُ اللَّهِ صلى الله عليه وسلم قَدْ قَبَضَ بِقَفَاىَ مِنْ وَرَائِي - قَالَ - فَنَظَرْتُ إِلَيْهِ وَهُوَ يَضْحَكُ فَقَالَ ‏"‏ يَا أُنَيْسُ أَذَهَبْتَ حَيْثُ أَمَرْتُكَ ‏"‏ ‏.‏ قَالَ قُلْتُ نَعَمْ أَنَا أَذْهَبُ يَا رَسُولَ اللَّهِ ‏.‏ قَالَ أَنَسٌ وَاللَّهِ لَقَدْ خَدَمْتُهُ تِسْعَ سِنِينَ مَا عَلِمْتُهُ قَالَ لِشَىْءٍ صَنَعْتُهُ لِمَ فَعَلْتَ كَذَا وَكَذَا أَوْ لِشَىْءٍ تَرَكْتُهُ هَلاَّ فَعَلْتَ كَذَا وَكَذَا ‏.‏

Anas reported that Allah's Messenger (PBUH) had the best disposition amongst people. He sent me on an errand one day, and I said: By Allah, I would not go. I had, however, this idea in my mind that I would do as Allah's Apostle (PBUH) had commanded me to do. I went out until I happened to come across children who had been playing in the street. In the meanwhile, Allah's Messenger (PBUH) came there and he caught me by the back of my neck from behind me. As I looked towards him I found him smiling and he said: Unais, did you go where I commanded you to go? I said: Allah's Messenger, yes, I am going. Anas further said: I served him for nine years but I know not that he ever said to me about a thing which I had done why I did that, or about a thing I had left as to why I had not done that. Translation Not Available

Book Ref: Sahih Muslim Book 43 Hadith 5724
Web Ref:  Sahih Muslim Book 30 Hadith 2310 a, 23