صحيح البخاري

Narrated Jabir bin `Abdullah:

We were in a Ghazwa (Sufyan once said, in an army) and a man from the emigrants kicked an Ansari man (on the buttocks with his foot). The Ansari man said, "O the Ansar! (Help!)" and the emigrant said. "O the emigrants! (Help!) Allah's Messenger (ﷺ) heard that and said, "What is this call for, which is characteristic of the period of ignorance?" They said, "O Allah's Messenger! A man from the emigrants kicked one of the Ansar (on the buttocks with his foot)." Allah's Messenger (ﷺ) said, "Leave it (that call) as is a detestable thing." `Abdullah bin Ubai heard that and said, 'Have the (the emigrants) done so? By Allah, if we return Medina, surely, the more honorable will expel therefrom the meaner." When this statement reached the Prophet. `Umar got up an, said, "O Allah's Messenger! Let me chop off the head of this hypocrite (`Abdullah bin Ubai)!" The Prophet (ﷺ) said "Leave him, lest the people say that Muhammad kills his companions." The Ansar were then more in number than the emigrants when the latter came to Medina, but later on the emigrant increased.