Muhammad bin Sirin said: A funeral passed by Sayyiduna Ibn Abbas and Sayyiduna al-Hasan bin Ali (may Allah be pleased with them both). One of them stood up and the other remained seated. The one standing said to the one sitting: "Did the Prophet (peace and blessings be upon him) not stand?" He said: "Yes indeed, but then he sat."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 2732