What does Matthew 25:31 mean?

Some scholars point to this passage, at the end of the Olivet Discourse (Matthew 24:3), as the most difficult to interpret in all of Matthew. Teachers and traditions have applied deeply contrasting views on the meaning of these verses. We will attempt to represent several of those views and to explain our best understanding of the passage. Ultimately, that obscurity should be a clue to the passage's level of importance: had it been critical for Christians to have nuanced understanding of these words, God would have made it plain.

After delivering several parables about how His followers should live while waiting for His return, Jesus now turns to a description of the judgment that will take place when He does return. This judgment is why Jesus tells those who would put their hope in Him to keep watch and to do the work He has given them to do.

Jesus has used the name Son of Man for Himself throughout Matthew's account (Matthew 8:20; 9:6; 12:8; 13:41; 16:27; 24:30). He uses that phrase here while describing the moment He will take His glorious throne after arriving on earth in glory with His angels. He will have returned as both the Judge and the King. This marks the beginning of His kingdom on earth, a period known to many as the "millennium," the 1,000–year reign of Christ. While opinions differ on the nature and timing of these events, that is our best understanding of the text.

Jesus' reign as King, in this depiction, begins with a judgment dividing people into two different groups.