What is the origin of the noble Hadith: "Support your brother whether he is an oppressor or oppressed"?

The aforementioned Hadith is authentic, narrated by Al-Bukhari, Ahmad, Al-Tirmidhi, and others. Its wording in Al-Bukhari, on the authority of Anas (may Allah be pleased with him), is that the Messenger of Allah (peace and blessings be upon him) said: "Support your brother whether he is an oppressor or oppressed." And supporting him when he is an oppressor was explained as preventing him or restraining him from his oppression.