Sunan Ibn Mājah 3270✓ 5Sahih
حَدَّثَنَا مُوسَى بْنُ عَبْدِ الرَّحْمَنِ، أَنْبَأَنَا أَبُو دَاوُدَ الْحَفَرِيُّ، عَنْ سُفْيَانَ، عَنْ أَبِي الزُّبَيْرِ، عَنْ جَابِرٍ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " لاَ يَمْسَحْ أَحَدُكُمْ يَدَهُ حَتَّى يَلْعَقَهَا فَإِنَّهُ لاَ يَدْرِي فِي أَىِّ طَعَامِهِ الْبَرَكَةُ " .
It was narrated from Jabir that the Messenger of Allah (ﷺ) said:"None of you should wipe his hand until he has licked it, for he does not know where the blessing if in his food.'"