Bayhaqi 10787 — Selling with disclaimer of defects

Salim bin Abdullah (may Allah have mercy on him) said that Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) sold a slave of his for 800 dirhams, and sold him declaring himself free of every defect. The man who had bought the slave from Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: The slave has a disease which you did not name. The two took their dispute to Sayyiduna Uthman bin Affan (may Allah be pleased with him). The man said: He sold me a slave who had a disease, and he did not tell me. Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said: I sold him with a release (from defects). Sayyiduna Uthman (may Allah be pleased with him) required Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) to swear an oath that, at the time he sold the slave, he knew of no disease in him. Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) refused to swear the oath and took the slave back. Later Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) sold that slave for 1,500 dirhams.
Imam Malik (may Allah have mercy on him) said: The agreed position among us is that whoever sells a slave, a slave girl or an animal with a release (from defects) is free of every defect, unless he knowingly concealed a defect. If he knowingly concealed a defect, his release will not benefit him, and what he sold will be returned to him.
Imam al-Shafi'i (may Allah have mercy on him) said concerning a person who sells a slave or an animal with a release from defects: What we follow, and Allah knows best, is the ruling of Sayyiduna Uthman bin Affan (may Allah be pleased with him): that he is free of every defect he did not know of, but not free of a defect he knew of and did not name.