Sahih Bukhari Volume 4, Book 56, Hadith 2889

حَدَّثَنَا مُحَمَّدُ بْنُ عَرْعَرَةَ، حَدَّثَنَا شُعْبَةُ، عَنْ يُونُسَ بْنِ عُبَيْدٍ، عَنْ ثَابِتٍ الْبُنَانِيِّ، عَنْ أَنَسِ بْنِ مَالِكٍ ـ رضى الله عنه ـ قَالَ صَحِبْتُ جَرِيرَ بْنَ عَبْدِ اللَّهِ، فَكَانَ يَخْدُمُنِي‏.‏ وَهْوَ أَكْبَرُ مِنْ أَنَسٍ قَالَ جَرِيرٌ إِنِّي رَأَيْتُ الأَنْصَارَ يَصْنَعُونَ شَيْئًا لاَ أَجِدُ أَحَدًا مِنْهُمْ إِلاَّ أَكْرَمْتُهُ

Narrated By Anas : I was in the company of Jabir bin 'Abdullah on a journey and he used to serve me though he was older than I. Jarir said, "I saw the Ansar doing a thing (i.e. showing great reverence to the Prophet) for which I have vowed that whenever I meet any of them, I will serve him."