It is enough of a lie for a man to narrate everything he hears

It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "It is enough of a lie for a person that he relates everything he hears (without verifying it), and it is enough of miserliness for a person that he says: 'I will take my full right and will not leave any of it.'"
This chain is sahih (authentic), because the forefathers of Hilal bin al-Ala' are trustworthy Imams, and Hilal was the Imam of the people of al-Jazirah in his time.

It is narrated from Sayyiduna Anas bin Malik (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) bought Sayyidah Safiyyah (may Allah be pleased with her) (from among the captives) from Dihyah al-Kalbi in exchange for seven persons (slaves).
This hadith is sahih (authentic) on the condition of Muslim, but the two Shaykhs did not record it.

It is narrated from Sayyiduna Uqbah bin Amir al-Juhani (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said concerning the period for returning slaves on account of a defect (uhdah): "It is three nights." Sa'id said: I asked Qatadah: "How will this work?" He said: "If the buyer finds a defect in the merchandise, he may return it within those three days and will not be asked for witnesses. But once those days have passed, he has no right to return it without evidence that he bought it while that defect was already in it; otherwise the seller is to take an oath that he did not sell it while it had an illness."