Narrated by AlMiqdam: The Prophet (The Blessings and Peace of Allah be upon him) said Nobody has ever eaten better food than that which he has earned by working with his own hands   .The Prophet of Allah David (Peace of Allah be upon him)used

to eat from the earnings of his manual labour." 

عن المقدام رضى الله عنه عن النبى صلى الله عليه وسلم قال: ما اكل احد طعاما قط خيرا من ان ياكل من عمل يده وان نبى الله داود عليه السلام كان ياكل من عمل يده "