Ibn'Abbaas Radiyallahu'Anhu says:
"Once when Rasulullah Sallailahu 'Alayhi Wasallam came out of the toilet, after relieving himself from the call of nature, food was served to him. They asked if water for wudu should be brought? He replied: 'I have been commanded to perform wudu when 1 perform salaah'".
Ibn 'Abbaas Radiyallahu 'Anhu relates:
"Rasulullah Sallallahu 'Alayhi Wasallam once, after relieving himself in the toilet, came out, and was served food. The Sahaabah inquired: 'Will you not perform wudu?'. Rasulullah Saliallahu 'Alayhi Wasallam replied: 'Do I have to perform salaah, that wudu must be performed?'"
Salmaan Faarisi Radiyallahu 'Anhu says:
"I have read in-the Tauraah, that performing wudu (washing the hands) after eating increases blessings. I mentioned this to Rasulullah Sallailahu 'Alayhi Wasallam. Rasulullah Sallallahu 'Alayhi Wasallam said: "Wudu before and after eating (washing the hands and mouth) increases blessings."