Sayyiduna Abdullah bin Amr (may Allah be pleased with them both) narrates: A man said: O Messenger of Allah, the funeral of a disbeliever passes by us; do you stand up for it? He (peace and blessings be upon him) said: "Yes, stand up for it; you are not standing for it, but rather for the angels who come with it."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 13644