Amir bin 'Abda عامر بن عبدة · The Book of Prayer - Funerals

Whenever you see a funeral procession, stand up for that until it moves away or is lowered on the ground.

Should any one of you come across a funeral procession, and if he does not intend to accompany it, he must stand up until it passes by him or is placed upon the ground before it passes him.