He was a companion of the Prophet. He said that whenever a funeral was brought to him and he found those following it to be few, he would arrange them into three rows and then perform the prayer over the deceased. He would say, "The Messenger of Allah ﷺ said, 'No deceased person has three rows of Muslims pray over him except that it is granted.'"
حدثنا أبو بكر بن أبي شيبة وعلي بن محمد قالا حدثنا عبد الله بن نمير عن محمد بن إسحق عن يزيد بن أبي حبيب عن مرثد بن عبد الله اليزني
وكانت له صحبة قال كان إذا أتي بجنازة فتقال من تبعها جزأهم ثلاثة صفوف ثم صلى عليها وقال إن رسول الله ﷺ قال ما صف صفوف ثلاثة من المسلمين على ميت إلا أوجب
Sourcing - the chain of transmission is daif. Abu Dawud narrated it in the Book of Funerals, in the chapter on standing in rows for the funeral prayer, hadith no. 3166, from the hadith of Ibn Ishaq with this wording. Tirmidhi graded it hasan, hadith no. 1028, as did Nawawi, while Hakim and Dhahabi graded it sahih.Ibn Ishaq transmitted it using ambiguous wording ("an"), and there is another serious flaw in it that invalidates it.