It is narrated from Sayyiduna Rafi' bin Khadij (may Allah be pleased with him) that it was asked from the Noble Prophet (peace and blessings be upon him): O Messenger of Allah! Which earning is the purest? He replied: A man's earning from his own hand and every blessed (honest) trade.
Hadith Referenceالفتح الربانی / كتاب البيوع والكسب والمعاش وما يتعلق بالتجارة / 5730