Yahya bin Abi Kathir (may Allah have mercy on him) says that the Messenger of Allah (peace and blessings be upon him) said: "Make a contract with them if you know any good in them" [Surah al-Nur: 33], meaning: if you see some skill or craft in them; and do not leave them to depend on people.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21601