Raja' bin Rabi'ah narrates: I was sitting in Madinah in the Prophet's Mosque in a circle that included Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) and Sayyiduna Abdullah bin Amr (may Allah be pleased with him). Meanwhile Sayyiduna Imam Hasan bin Ali (may Allah be pleased with him) passed by and gave the greeting of peace. The people returned his greeting, but Sayyiduna Abdullah bin Amr (may Allah be pleased with him) remained silent. When he had gone, Sayyiduna Abdullah bin Amr (may Allah be pleased with him) said: "Wa alaykas-salamu wa rahmatullah (And upon you be peace and the mercy of Allah)." Then he said: "This man is the most beloved of the people of the earth to the people of the heavens. By Allah, I have not spoken with him since the battle of Siffin." Sayyiduna Abu Sa'id (may Allah be pleased with him) said: "Why do you not go to him and offer him your apology?" Sayyiduna Abdullah (may Allah be pleased with him) said: "Very well." The narrator says: Then they got up. Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) entered the house of Sayyiduna Imam Hasan (may Allah be pleased with him); he asked permission and Sayyiduna Imam Hasan (may Allah be pleased with him) gave him permission. Then he asked permission for Sayyiduna Abdullah bin Amr (may Allah be pleased with him), and he too came in. Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) said to Sayyiduna Abdullah bin Amr (may Allah be pleased with him): "Tell (us) what you told us when Hasan passed by." He said: "Very well, I will tell you: he is the most beloved of the people of the earth to the people of the heavens." Sayyiduna Imam Hasan (may Allah be pleased with him) said to him: "Since you know that I am the most beloved of the people of the earth to the people of the heavens, why then did you fight us at Siffin (the narrator is unsure; perhaps the words are:) or join it and increase the numbers (of our opponents)?" Sayyiduna Abdullah (may Allah be pleased with him) said: "By Allah, I neither increased the numbers of the people nor struck with a sword alongside them; I was only present with my father." Sayyiduna Imam Hasan (may Allah be pleased with him) said: "Do you not know that there is no obedience to a creature in disobedience to Allah Almighty?" Sayyiduna Abdullah (may Allah be pleased with him) replied: "Yes! In the blessed time of the Prophet (peace and blessings be upon him), I used to keep voluntary fasts continuously. My father complained about me to the Prophet (peace and blessings be upon him), saying: 'O Messenger of Allah, Abdullah bin Amr fasts during the day and keeps praying voluntary prayers at night.' The Prophet (peace and blessings be upon him) said: 'Keep voluntary fasts and also leave them off; (at night) sleep and also pray voluntary prayers, for I pray voluntary prayers and also sleep, and I keep voluntary fasts and also leave them off.' And the Prophet (peace and blessings be upon him) said: 'O Abdullah, obey your father.' So when my father set out on the occasion of the battle of Siffin, I too set out with him."
Al-Bazzar recorded it, and its narrators are the narrators of the Sahih, except for Hashim bin al-Barid, and he is thiqah (trustworthy). (Allamah Haythami says:) I say: Another chain of this report will also come in the chapter on the virtues of Sayyiduna Imam Husayn (may Allah be pleased with him).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب المناقب / 15044