Musannaf Ibn Abi Shaybah

Hazrat Umar (may Allah be pleased with him) wrote to Umair bin Sa’d: "To proceed: Prevent the Muslims with you from making their slaves write contracts of emancipation at the request of people."

Hazrat Ibn Umar (may Allah be pleased with both of them) disliked that a slave be made a mukatab without assigning him a profession.

Hazrat Ibn Umar (may Allah be pleased with both of them) made his slave a mukatab (one who has a contract of manumission). The slave came to him with an installment of the contract payment. When he arrived, Hazrat Ibn Umar (may Allah be pleased with both of them) asked, "Where did you get this from?" The slave replied, "I begged from people and did some work." Hazrat Ibn Umar (may Allah be pleased with both of them) said, "Do you want to feed me the filth of people's wealth? Go, you are free, and take your installment as well."

Hazrat Salman intended to make his slave a mukatab, then asked him, "From where will you bring the money?" He replied, "By begging from people." Hazrat Salman said, "Do you want to feed me the filth of people?" Then he refused to make him a mukatab.

Hazrat Aamir (may Allah have mercy on him) says that if you wish, you may make someone a mukatab, and if you wish, you may not.

Hazrat Ibn Abbas (may Allah be pleased with both of them) made his slave a mukatab and set a condition upon him that he would not ask people (for anything).