Kriterier för sanna återberättelser (hadither) om profeten Muhammad.

And test the orphans [in their abilities] until they reach marriageable age (al-nikaah). Then if you perceive in them sound judgement, release their property to them. And do not consume it excessively and quickly, [anticipating] that they will grow up. And whoever, [when acting as guardian], is self-sufficient should refrain [from taking a fee]; and whoever is poor - let him take according to what is acceptable. Then when you release their property to them, bring witnesses upon them. And sufficient is Allah as Accountant.

Abu Huraira said, "Allah's Messenger (ﷺ) led us in one of the two `Isha' prayers (Abu Huraira named that prayer but I forgot it)." Abu Huraira added, "He prayed two rak`at and then finished the prayer with Taslim. He stood up near a piece of wood Lying across the mosque and leaned on it in such a way as if he was angry. Then he put his right hand over the left and clasped his hands by interlacing his fingers and then put his J right cheek on the back of his left hand. The people who were in haste left the mosque through its gates. They wondered whether the prayer was reduced. And amongst them were Abu Bakr and `Umar but they hesitated to ask the Prophet. A long-handed man called Dhul- Yadain asked the Prophet, 'O Allah's Messenger (ﷺ)! Have you forgotten or has the prayer been reduced?' The Prophet (ﷺ) replied, 'I have neither forgotten nor has the prayer been reduced' The Prophet (ﷺ) added, 'Is what Dhul Yadain has said true?' They (the people) said, 'Yes, it is true.' The Prophet (ﷺ) stood up again and led the prayer, completing the remaining prayer, forgotten by him, and performed Taslim, and then said, 'Allahu Akbar.' And then he did a prostration as he used to prostrate or longer than that. He then raised his head saying, 'Allahu Akbar; he then again said, 'Allahu Akbar', and prostrated as he used to prostrate or longer than that. Then he raised his head and said, 'Allahu Akbar.' " (The subnarrator added, "I think that they asked (Ibn Seereen) whether the Prophet (ﷺ) completed the prayer with Taslim. He replied, "I heard that `Imran bin Husain had said, 'Then he (the Prophet) did Taslim.")

Reference : Sahih al-Bukhari 482
In-book reference : Book 8, Hadith 129
USC-MSA web (English) reference : Vol. 1, Book 8, Hadith 469
(deprecated numbering scheme)