Umm al-Mu’minin Umm Salamah (may Allah be pleased with her) reports that the Messenger of Allah (peace and blessings of Allah be upon him) said:“When any of you has a mukatab slave who possesses enough money to pay the price of his contract, then he should conceal this from him.” Imam Tirmidhi says:
1- This hadith is hasan sahih.
2- The people of knowledge act upon this hadith out of piety, righteousness, and caution. They say that a mukatab slave does not become free until he pays the price of his contract, even if he possesses enough money to pay it.