Sa'id bin al-Musayyib narrated: Sayyiduna Hassan (may Allah be pleased with him) recited poetry in the mosque, and Sayyiduna Umar (may Allah be pleased with him) passed by him. He looked at him with displeasure and said: In the mosque? In the mosque? Hassan said: By Allah! I have recited here in the presence of one who was better than you. The narrator said: He feared that he would cite the Messenger of Allah (peace and blessings be upon him), so he let the matter pass and left him.
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3572