From Sahih Bukhari (Hadith 3837):
Narrated `Abdur-Rahman bin Al-Qasim:Al-Qasim used to walk in front of the funeral procession. He used not to get up for the funeral procession (in case it passed by him). And he narrated from `Aisha that she said, "The people of the pre-Islamic period of ignorance used to stand up for the funeral procession. When they saw it they used to say twice: 'You were noble in your family. What are you now?
Reference: Bukhari 3837