It is narrated from Sayyiduna Rafi' bin Khadij (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) was asked: Which earning is best? He (peace and blessings be upon him) said: "A man's work with his own hand, and every honest (mabrur) trade."
Hadith Referenceالمعجم الكبير للطبراني / باب الراء / 4396