Sunan Ibn Majah
1539
Sahih+3

It was narrated from Abu Hurairah that the Prophet (ﷺ) said:“Whoever offers the funeral prayer will have one Qirat and whoever awaits until (the burial) is finished will have two Qirat.” They said: ‘What are these two Qirat?’ He said: ‘Like two mountains.’”

SahihAl-Albani
SahihMuhammad Fouad Abd al-Baqi