Tawus (may Allah have mercy on him) said: If a sick person makes an acknowledgement in favour of his heir or a non-heir, it is valid. Imam al-Bukhari (may Allah have mercy on him) said: Al-Hasan (may Allah have mercy on him) said: The time when a man most deserves to be believed is when it is his last day in this world and his first day in the Hereafter. And Sayyiduna Rafi' bin Khadij (may Allah be pleased with him) left instructions that the wealth locked behind the door of his wife al-Fazariyyah was not to be opened. Some people said: His acknowledgement in favour of his heir is not valid, because of suspicion. The Prophet (peace and blessings be upon him) said: "Beware of suspicion, for suspicion is false speech." And the wealth of Muslims is not lawful, because of the saying of the Prophet (peace and blessings be upon him): "The sign of the hypocrite is also that when he is entrusted, he betrays." And Allah Almighty says: "Indeed, Allah commands you to render trusts to whom they are due." [Surah al-Nisa: 58] So He did not single out an heir or anyone else.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإقرار / 11456
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "Beware of suspicion, for suspicion is false speech. Do not look for others' faults, do not spy, do not compete with one another, do not envy one another, do not bear hatred, do not speak ill of anyone behind his back, and, O servants of Allah, be brothers."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإقرار / 11457
It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "The signs of a hypocrite are three: when he speaks he lies, when he is entrusted he betrays, and when he promises he breaks his promise."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإقرار / 11458
Ja'far bin Muhammad (may Allah have mercy on him) narrates from his father (may Allah have mercy on him) that the Prophet (peace and blessings be upon him) said: "There is no bequest for an heir, nor any acknowledgement of debt."
Abbad bin Kathir narrated it from Nuh without mentioning Jabir, so it is munqati' (broken); its narrator is da'if (weak), and one like him is not used as proof.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإقرار / 11459
Yahya bin Ma'in (may Allah have mercy on him) said: Nuh bin Darraj was a wicked liar; he served as a judge for years while blind (and in another place he said: three years), and out of his wickedness he would not tell people that he was blind. He had no knowledge of hadith and was not good at anything.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الإقرار / 11460