Anas bin Sirin (may Allah have mercy on him) narrates from his father: Sayyiduna Anas bin Malik (may Allah be pleased with him) made a kitabah contract with me for 20 thousand dirhams. I was among those who conquered Tustar; I bought goods and made a profit. I came to Sayyiduna Anas bin Malik (may Allah be pleased with him) with the kitabah amount, but he refused to accept it, (accepting) only the fixed instalments. I mentioned this to Sayyiduna Umar (may Allah be pleased with him), and he said: "Anas wants the inheritance." And he wrote to him: "Accept it from him." So he accepted it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21707
Sa'id bin Abi Sa'id al-Maqburi (may Allah have mercy on him) narrates from his father, who said: A woman from Banu Layth bought me in the market of Dhu al-Majaz for 700 dirhams. Then I came to Madinah, and she made a contract of manumission (mukatabah) with me for 40,000 dirhams. I paid her most of that amount, then I carried what remained to her and said: Take possession of your money. She said: By Allah, (no,) I will take it month by month and year by year. I went and mentioned this to Sayyiduna Umar bin al-Khattab (may Allah be pleased with him), and he said: Deposit the money in the public treasury (Bayt al-Mal). And he sent word to her: Your money is in the public treasury, and Abu Sa'id is free; if you wish, you may keep taking it month by month and year by year. He said: Then she took the money.
Abu Bakr al-Naysaburi said: This hadith is hasan (good).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21708
Abu Bakr says that a man made a contract of manumission with his slave, fixing it in set installments. The slave brought his entire contract payment, but he refused to take it except in installments. He came to Sayyiduna Umar (may Allah be pleased with him), and Sayyiduna Umar (may Allah be pleased with him) summoned his master and offered him the payment, but he refused to take it. Sayyiduna Umar (may Allah be pleased with him) said: I will deposit it in the public treasury. And he said to the master: Take your fixed installments, and he said to the mukatab: Go wherever you wish.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21709
Ibn Awn narrates from Muhammad that a mukatab said to his master: Collect your contract payment from me. He said: No, only in fixed installments. He came to Sayyiduna Uthman (may Allah be pleased with him) and mentioned this to him, so he summoned the master and said: Take your contract payment. He refused, saying: I will take only the fixed installments. Sayyiduna Uthman (may Allah be pleased with him) had the money brought and placed it in the public treasury, freed him, and said: I will pay you your portion. When he saw this, he then took the money.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب المكاتب / 21710