Matthew 25:31 - 46
ESV - 31 When the Son of Man comes in his glory, and all the angels with him, then he will sit on his glorious throne. 32 Before him will be gathered all the nations, and he will separate people one from another as a shepherd separates the sheep from the goats.
For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
The immediate context of Matthew 25:31-46 is the sheep and goat judgment. My "brethren" refers to the Jewish people in the first instance, but also has a wider application of all believers and any person.