"The Messenger of Allah said: 'When you see a funeral, stand up, and whoever follows it, let him not sit down until (the body) is placed (in the grave)." (Using translation from Nasāʾī 1917)  

قَالَ رَسُولُ اللهِ ﷺ «إِذَا رَأَيْتُمُ الْجِنَازَةَ فَقُومُوا فَمَنْ تَبِعَهَا فَلَا يَقْعُدَنَّ حَتَّى تُوضَعَ»