رِيَاضُ الصَّالِحِينَ
Riyad as-Salihin 747
The Book About the Etiquette of Eating
Excellence of Eating with Three Fingers and Licking Them
عَنِ ابْنِ عَبَّاسٍ رضى اللَّه عَنْهُمَا قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّه عَلَيْهِ وَسَلَّمَ: إِذَا أَكَلَ أَحَدُكُمْ طَعَامًا، فَلاَ يَمْسَحْ أصابعه حَتَّى يَلْعَقَهَا أَوْ يُلْعِقَهَا . ((مُتَّفَقٌ عَلَيْهِ))
Ibn 'Abbas (May Allah be pleased with them) reported: Messenger of Allah (ﷺ) said, "When one of you finishes eating, he should not wipe his fingers until he has licked them himself or has given them to someone else to lick for him." [Al-Bukhari and Muslim].
Riyad as-Salihin, 747