The Messenger of Allah (sal Allahu alaihi wa sallam) said: “The cleanest food is that which a man earns by his own hands.” [Bukhari]
The most pure food, in terms of its being Halal and making its consumer’s body befitting for Paradise, is food that is earned with one’s physical labour.
Once Imam Auzai saw Ibraheem bin Adham carrying a load of fuel on his back. So Imam Auzai said to him, “O Abu Ishaq, why are you taking such trouble? Our brothers are sufficient for your (to take care of your needs).” Ibraheem bin Adham replied, “O Abu Amer, leave me alone in this matter, as I have come to know that if a man waits in a place of disgrace in search of lawful livelihood, Paradise is assured for him.” [Ihya Ulum Id-Deen]