The Holy Prophet (S) said: "There are seventy branches of worship, the best of which is earning a living lawfully."
At-Tahthib, vol. 6, p. 324
Imam Amir ul Mu'mineen ‘Ali (‘a) said: "Never, never will prosperity be reached by remaining idle and lazy."
Imam al-Baqir, the fifth Imam (‘a) said: "Avoid laziness and discontent. These two are the keys to every vice."
Bihar-ul-Anwar, vol. 78, p. 175
When Sa'd Ansari responded to the Holy Prophet (S) that his hands were calloused because he used to work with a rope and a shovel to earn money to spend for his wife and children, he (S) kissed his hand (as an honour) and said: "This is a hand which the Fire (of Hell) will never touch."
Usd-ul-Ghabah, vol. 2, p. 269