This excerpt is taken from Sheikh Abu Hamza Abdul Khaliq Siddiqi's book Sahi Fazail-e-Amaal.
Sayyiduna Sinan bin Sanah narrates that the Messenger of Allah, peace and blessings be upon him, said:
الطاعم الشاكر له مثل أجر الصائم الصابر
"A grateful eater has the reward and recompense like that of a patient fasting person."
Reference: Musnad Ahmad: 343/4.
Sheikh Shoaib has classified it as Hasan.Sayyiduna Anas bin Malik, may Allah be pleased with him, says that when the Messenger of Allah, peace and blessings be upon him, ate, he would lick his three fingers. And the Messenger of Allah, peace and blessings be upon him, said:
"When any one of you drops a bite, let him remove the dirt from it and eat it, and do not leave it for Satan."
And He commanded us to clean the utensils, (explaining the reason) "You do not know in which part of your food there is blessing."
Reference: Sahih Muslim, Book of Drinks, Chapter on the recommendation of licking fingers and the bowl ......, Hadith No: 2034.