It is narrated from Muhammad bin Sirin that a funeral passed by Ibn Abbas and Hasan bin Ali (may Allah be pleased with them). One of them stood up and the other remained seated. The one who had stood up said: Do you not know that the Messenger of Allah (peace and blessings be upon him) stood up? The other said: Yes, indeed. And then he sat down.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12818