Sunan an-Nasa'i 1914
سنن النسائي#1914SahihIt was narrated from Abu Sa'eed that the Messenger of Allah said:"When a funeral passes by you, stand up, and whoever follows it, let him not sit down until it is put down (in the grave)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiSahih - Agreed Upon
In-book reference: 21:97