Can we give anything to Christ?
When the psalmist cried out, "What shall I render to the Lord for all of his benefits to me?" the reply was, "I will lift the cup of salvation and call upon the name of the Lord" (Psalm 116:12-13). So, translating that into Christmas: Jesus gives us the gift of himself and we ask, "Now what can I render to Jesus for all the benefits of his fellowship?" Answer: Ask him for his help. That's the gift he wants.
The reason Christ wants this is because he always wants to get the glory while we get the benefit. Glory comes to him when we depend on him rather than try to enrich him. If we come to him with gifts—as though he needed something—then we put him in the position of a needy person, and we're the benefactors. He always wants to be the one who is infinitely self-sufficient. Therefore the only gifts that we can bring Jesus are gifts of praise, thanks, longing, and neediness.
A fountain is not glorified by us hauling buckets of dirty water up the mountain and pouring them in. A fountain—a spring in a mountain—is glorified, rather, by us lying down at the edge of the stream, putting our face in, drinking our fill, and getting up and saying, "Ah!" That's called worship. Then we take a bucket, dip it in, walk down the hill to the people in the valley who don't know that the spring exists, and we say, "Taste this! It's right up there, and his name is Jesus!" The kind of gift that the fountain wants is drinkers, because then he looks truly overflowing, rich, and self-sufficient. And that's exactly what he wants to look like.
But aren't we giving to God when we give to the poor (Matthew 25:40)?
Yes, but what is the something? Jesus is clearly in heaven today, risen, triumphant, and supplying everything we take to the poor. That's an absolutely clear teaching: "My God will supply all your needs according to his riches in glory in Christ Jesus" (Philippians 4:19).
So if you have anything to take to a prisoner, any clothes to put on the naked, any drink to give to the thirsty, any fellowship to give to the refugee, you're getting that from Jesus. You can't be enriching Jesus. So what are you giving Jesus? You're giving him honor, tribute, and glory.
Remember also that in this text Jesus calls these beneficiaries "my brethren." That means that if you give to the poor then you're choosing to bless, at your own cost, the brothers of Jesus. You're treating them with honor because they belong to Jesus.
Jesus doesn't need the food or the clothing. What he delights in is receiving the honor that his name gets when we chose to say, "It's his brothers that I'm going to love and sacrifice for." So as long as we talk about giving to Jesus—in terms of Matthew 25:40—we should understand that what is happening there is that Christ is being honored, glorified, and valued, because these are Christ's brothers that we are willing to serve.