That Messenger of Allah ﷺ said: "When one of you eats, then let him lick his fingers, for indeed he does not know in which of them is the blessing." He said: There are narrations on this topic from Jabir, Ka'b bin Malik, and Anas.  

قَالَ رَسُولُ اللَّهِ ﷺ إِذَا أَكَلَ أَحَدُكُمْ فَلْيَلْعَقْ أَصَابِعَهُ فَإِنَّهُ لاَ يَدْرِي فِي أَيَّتِهِنَّ الْبَرَكَةُ قَالَ وَفِي الْبَابِ عَنْ جَابِرٍ وَكَعْبِ بْنِ مَالِكٍ وَأَنَسٍ