A lot of times, people use the end of this chapter to talk about how we are to be kind to all the hurting people in the world: the sick, the poor, the hungry, and those in prison.
Of course, this is true.
However, this passage is actually a little more focused than that.
Jesus said,
Truly I tell you, whatever you did for one of the least of these brothers and sisters of mine, you did for me. (Matthew 25:40)
Question: Who are “these brothers and sisters of mine?”
Look at all the times that Jesus uses the terms of “my brothers” or “my brothers and sisters.” (Matthew 12:50, Matthew 28:10, John 20:17).
Take a look also at verses like Luke 10:40, 42. Look at Acts 9:1, 4-5.
What you see is that when Jesus talks about his brothers and sisters, he’s talking about people who follow him.
One of tests of a true follower of Jesus is this: do we love our brothers and sisters? If we don’t there is something wrong.
That’s why John said this,
If anyone says, “I love God,” and yet hates his brother or sister, he is a liar.
For the person who does not love his brother or sister whom he has seen cannot love God whom he has not seen.
And we have this command from him: the one who loves God must also love his brother and sister. (1 John 4:20-21)
How do we treat our brothers and sisters in Christ? What does it say about our love for God?
Moment to Moment (Bible blog) 