Sahih Muslim , Book 36, Hadith 171 (In-Book) ⓘ
Ibn Ka'b b. Malik reported on the authority of his father that the Messenger of Allah used to eat (food) with three fingers and he licked his hand before wiping it (with towel).
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا أَبُو مُعَاوِيَةَ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ عَبْدِ الرَّحْمَنِ، بْنِ سَعْدٍ عَنِ ابْنِ كَعْبِ بْنِ مَالِكٍ، عَنْ أَبِيهِ، قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يَأْكُلُ بِثَلاَثِ أَصَابِعَ وَيَلْعَقُ يَدَهُ قَبْلَ أَنْ يَمْسَحَهَا .
also referenced under: Hadith 2032 (Reference) & Book 23, Hadith 5040 (USC-MSA)