Sayyiduna Ibn Abbas (may Allah be pleased with them both) narrates from Sayyiduna Abbas (may Allah be pleased with him) that he said: "O Messenger of Allah (peace and blessings be upon him), we recognise rancour and enmity in the faces of some people." He (peace and blessings be upon him) asked: "By what do you recognise it?" He said: "People sit in a circle talking, and when I come upon them they stop (talking) because of my kinship with you (peace and blessings be upon him); yet if they were sincere to Allah and His Messenger (peace and blessings be upon him), they would not stop because of my kinship with you (peace and blessings be upon him)." He (peace and blessings be upon him) asked: "Do you recognise them?" He said: "Yes." Then Sayyiduna Abbas (may Allah be pleased with him) put his hand on the forearm of the Prophet (peace and blessings be upon him), and then he entered the mosque, and Sayyiduna Abbas (may Allah be pleased with him) said to him (peace and blessings be upon him): "This circle is of them." So the Prophet (peace and blessings be upon him) took hold of Sayyiduna Abbas's (may Allah be pleased with him) hand, raised it, and said: "Whoever does not love this uncle of mine for the sake of Allah and because of his kinship with me is not a believer."
No one narrated this hadith from Mansur except Ibn al-Ajlah (may Allah have mercy on him).