Matthew 24 dealt with when the Son of Man would return. This chapter deals with what will happen when he returns: judgment.
All the nations will be gathered before him, as he sits on his throne as the King (31-32). And he will separate the nations not by nationality or ethnicity, but by whether they are sheep or goats. In the end, these are the only two ethnicities or nationalities that will matter.
Those who are sheep have come to that only and all by grace - only because they were “blessed by (Jesus’) Father” before they were ever born (34). It’s all by His sovereign grace. But what is the tell-tale sign that someone is a sheep and not a goat? The old song is so true: “They will know we are Christians by our love.” To each other? To outsiders? No, to Jesus himself:
Matthew 25:35–36 (ESV): For I was hungry and you gave me food, I was thirsty and you gave me drink, I was a stranger and you welcomed me, 36 I was naked and you clothed me, I was sick and you visited me, I was in prison and you came to me.’
Of course, the sheep, having been separated into their own group, will then ask the King, “when did we do all these things” (37-39)? Jesus’ reply demands reflection by each of us in the modern church (emphasis mine):
Matthew 25:40 (ESV): And the King will answer them, ‘Truly, I say to you, as you did it to one of the least of these my brothers, you did it to me.’
We are the body of Christ, and thus when we feed and nurture the “least” of our fellow Christians, we are doing it to Christ himself. We are loving Christ. And the opposite is true of the goats: their condemnation is based on their cold response to Christ’s body on earth (41-46).
Note that Jesus is not calling us here to love everyone who is down and hurting. Yes, love your neighbor, in Jesus’ name. But at the final judgment Jesus will put special emphasis on whether we loved him, and he says that we love him not by feeding the homeless in general, but by meeting the unmet needs of life of our siblings in the church.
At the end of time, Jesus will be much more concerned with what we did with poor widows than the excellence of our worship music. He will ask if we identified with our brothers who were persecuted or jailed, or if we distanced ourselves from them and critiqued them. Look around your church; love Jesus himself, in “the least of these.”