Mukhtasar Muslim

Narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that Sayyiduna Umar bin Khattab (may Allah be pleased with him) passed by Sayyiduna Hassan (may Allah be pleased with him) while he was reciting poetry in the mosque. (It is understood that reciting poetry in the mosque which praises Islam, criticizes disbelievers, or encourages jihad is permissible.) Sayyiduna Umar (may Allah be pleased with him) looked at him (angrily). Sayyiduna Hassan (may Allah be pleased with him) said, "I used to recite poetry in the mosque even when a person better than you (i.e., the Prophet Muhammad, peace and blessings be upon him) was present." Then he looked towards Sayyiduna Abu Hurairah (may Allah be pleased with him) and said, "I ask you by Allah, did you hear from the Messenger of Allah (peace and blessings be upon him)? He used to say: 'O Hassan! Reply on my behalf. O Allah, help him with the Holy Spirit (Jibreel, peace be upon him).'" Sayyiduna Abu Hurairah (may Allah be pleased with him) said, "Yes, I heard it. O Allah, You know."