Sheep or Goats
Matthew begins his record of Jesus teaching with the Sermon on the Mount, and that sermon finishes with the parable of the houses built on rock or sand, a parable of reward and judgement. And, significantly, Matthew finishes his account of Jesus teaching with this story of the last judgement.
Jesus tells them that when the Son of Man returns in glory he will sit on the throne of his glory and the reason he sits is to judge. There's a cataclysmic nature to Jesus return. I think we sometimes imagine a scene where people are hanging around for Jesus to call them in to the courthouse. But here the judgement is closely tied to his return. This is reminiscent of the passage in Phil 2 where we read that at the name of Jesus every knee shall bow and every tongue confess that he's Lord. There's to be a spontaneous response to his return.
All the nations will be gathered before him. No one will escape this judgement. Whatever nationality or religion, whether they're Jew, Christian, Hindu, Buddhist or Muslim, they'll all be there, gathered around the throne with the angels looking on. And he'll separate them from one another. There's a strong sense here of the decision being taken out of our hands. We're now under Jesus authority and he has the power to do with us what he wishes.
And Jesus knows what his people are like, just as a shepherd is able to distinguish easily which of his flock are sheep or goats. He puts one lot on his right hand and the others on his left. Then he pronounces the judgement.
To those on his right he says 'Come, you that are blessed by my Father, inherit the kingdom prepared for you from the foundation of the world'