مِشْكَاةُ الْمَصَابِيحِ
Mishkat al-Masabih 4164
Foods
Section 1
وَعَنْ كَعْبِ بْنِ مَالِكٍ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَأْكُلُ بِثَلَاثَةِ أَصَابِعَ وَيَلْعَقُ يَدَهُ قَبْلَ أَن يمسحها. رَوَاهُ مُسلم
Ka'b b. Malik said that God's messenger used to eat with three fingers and lick his hand before wiping it. Muslim transmitted it.
Mishkat al-Masabih, 4164صَحِيح (الألباني)