I asked him about a man who said: "My slave is free, but he must work for me for such-and-such a number of years." Imam (as) said: "He is free, but he is obligated to fulfill the work." I said: "Ibn Abi Layla claims that he is free and is not obligated to do anything." Imam (as) said: "He has lied! Indeed, Imam Ali ibn Abi Talib (as) freed Abu Nayzar, 'Iyad, and Riah, while requiring them to work for such-and-such a number of years. They were provided with their sustenance and clothing in a reasonable manner during those years."