Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) says: We were with the Prophet (peace and blessings of Allah be upon him) in a battle. A Muhajir struck an Ansari on the buttocks with his hand or foot. The Ansari, considering it an issue of family honor and zeal, called out to the Ansar: "O Ansar!" In response, the Muhajir said: "O Muhajirun!" The Messenger of Allah (peace and blessings of Allah be upon him) heard this and said: "What are these calls of ignorance?" They said: O Messenger of Allah! A Muhajir teased an Ansari, (because of this these calls started). He (peace and blessings of Allah be upon him) said: "Leave these (associations), they are filthy." Sayyiduna Jabir (may Allah be pleased with him) says: When the Prophet (peace and blessings of Allah be upon him) came to Madinah, the number of Ansar was greater, but later the number of Muhajirun also increased. When Abdullah bin Ubayy the hypocrite heard this, he said: Have these people reached this stage? When we return to Madinah, we, the honorable ones, will expel these lowly ones from Madinah. Sayyiduna Umar (may Allah be pleased with him) said: (O Messenger of Allah!) Give me permission, I will behead this hypocrite. The Prophet (peace and blessings of Allah be upon him) said: "Leave him, lest people start saying that Muhammad (peace and blessings of Allah be upon him) kills his own companions."