Sahih Bukhari Volume 9, Book 87, Hadith 6913

حَدَّثَنِي عَمْرُو بْنُ زُرَارَةَ، أَخْبَرَنَا إِسْمَاعِيلُ بْنُ إِبْرَاهِيمَ، عَنْ عَبْدِ الْعَزِيزِ، عَنْ أَنَسٍ، قَالَ لَمَّا قَدِمَ رَسُولُ اللَّهِ صلى الله عليه وسلم الْمَدِينَةَ أَخَذَ أَبُو طَلْحَةَ بِيَدِي فَانْطَلَقَ بِي إِلَى رَسُولِ اللَّهِ صلى الله عليه وسلم فَقَالَ يَا رَسُولَ اللَّهِ إِنَّ أَنَسًا غُلاَمٌ كَيِّسٌ فَلْيَخْدُمْكَ‏.‏ قَالَ فَخَدَمْتُهُ فِي الْحَضَرِ وَالسَّفَرِ، فَوَاللَّهِ مَا قَالَ لِي لِشَىْءٍ صَنَعْتُهُ، لِمَ صَنَعْتَ هَذَا هَكَذَا وَلاَ لِشَىْءٍ لَمْ أَصْنَعْهُ لِمَ لَمْ تَصْنَعْ هَذَا هَكَذَا

Narrated By 'Abdul-'Aziz : Anas said, "When Allah's Apostle arrived at Medina, Abu Talha took hold of my hand and brought me to Allah's Apostle and said, "O Allah's Apostle! Anas is an intelligent boy, so let him serve you." Anas added, "So I served the Prophet L at home and on journeys; by Allah, he never said to me for anything which I did: Why have you done this like this or, for anything which I did not do: 'Why have you not done this like this?"