Sayyiduna Salman al-Farsi رضي الله عنه Radiallahu anhu relates that he read in the Tawrah that washing the hands after meals was a source of prosperity. He related this to Nabi Sallallahu Alaihi Wasallam, who said to him, "Washing the hands before as well as after meals is a source of barakah (blessings)." - Shama'il