When the Prophet ﷺ passed away, there were two men in Medina, one who dug graves with a side niche and another who dug them as a straight trench. The people said, "Let us seek guidance from our Lord and send for both of them. Whichever one arrives first, we will leave the matter to him." So they sent for them, and the one who dug graves with a side niche arrived first, so they prepared a grave with a side niche for the Prophet ﷺ.
لما توفي النبي ﷺ كان بالمدينة رجل يلحد، وآخر يضرح، فقالوا: نستخير ربنا ونبعث إليهما، فأيهما سبق تركناه، فأرسل إليهما، فسبق صاحب اللحد، فلحدوا للنبي ﷺ.
Ibn Majah (1557) narrated it from Mahmud bin Ghaylan, who said, Hashim bin Qasim told us, who said, Mubarak bin Fadala told us, who said, Humayd Tawil told me, from Anas, and he mentioned it. Hashim bin Qasim is Abu Nadr, the teacher of Imam Ahmad. Imam Ahmad narrated it from him in his Musnad (12415) in similar fashion.Its chain of transmission is hasan because of Mubarak bin Fadala, for he is "truthful, but he practices tadlis and smooths over defects." Abu Zura said, He practices tadlis frequently, but when he says "he told us," he is trustworthy. Here he has explicitly stated the mode of transmission, and the rest of the narrators in the chain are trustworthy. Hafiz graded it hasan in Talkhis (2/128). Busiri said, "Its chain of transmission is sahih and its narrators are trustworthy," but the correct view is as I have stated.