There were two grave-diggers in Medina, one who would dig a side-niche (lahd) and the other who would dig a straight trench (shaqq). They waited to see which of the two would arrive, and the one who dug the side-niche came, so he prepared a side-niche grave for the Messenger of Allah ﷺ.
كان بالمدينة حفاران، أحدهما يلحد، والآخر يشق فانتظروا أن يجئ أحدهما فجاء الذي يلحد، فلحد لرسول الله ﷺ.
Ibn Saad (2/295) narrated it from Yazid bin Harun and Hisham Abu Walid Tayalisi, from Hammad bin Salama, from Hisham bin Urwa, from his father, from Ayesha, and mentioned it as stated. Its chain of transmission is sahih.With the same meaning, Imam Ahmad (4762, 25041) and Ibn Saad also narrated it, both from Waki, who said, Umari related to us, from Nafi, from Ibn Umar, and Abdul-Rahman bin Qasim, from his father, from Ayesha, that the Prophet ﷺ was buried in a niche grave (lahd) made for him.Umari here is Abdullah bin Umar bin Hafs Madani, who is daif in both chains, the first being Waki from him, from Nafi, and the second being Waki from him, from Abdul-Rahman bin Qasim.It has also been narrated from her that she said, "When the Messenger of Allah ﷺ died, they disagreed about whether to make a niche grave (lahd) or a trench grave (shaqq), until they spoke sharply about it and their voices rose." Umar said, "Do not raise your voices near the Messenger of Allah ﷺ, neither living nor dead," or words to that effect. So they sent for both the one who made trench graves and the one who made niche graves. The one who made niche graves came, and he made a niche grave for the Messenger of Allah ﷺ, and then he was buried.Ibn Majah (1558) narrated this, but it contains Ubayd bin Tufayl Muqri, who is majhul (unknown), as stated in Taqrib, and his teacher Abdul-Rahman bin Abu Mulaykah is daif by the consensus of the scholars.