In Matthew 25:35–40, Jesus says:
“I was hungry and you gave me food, I was thirsty and you gave me drink, I was a stranger and you welcomed me, I was naked and you clothed me, I was sick and you visited me, I was in prison and you came to me.”
Then the righteous will answer him, saying, “Lord, when did we see you hungry and feed you, or thirsty and give you drink? And when did we see you a stranger and welcome you, or naked and clothe you? And when did we see you sick or in prison and visit you?”
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.”
New Testament scholar Craig Blomberg comments:
The majority perspective has understand Jesus’ ‘brothers’ in verse 40 to refer to spiritual kin, as the term (adelphoi) does elsewhere in Matthew in every instance in which biological siblings are not in view (see 5:22–24, 47; 7:3–5; 12:48–50; 18:15 twice, 21, 35; 23:8; 28:10).
The term ‘little ones’, of which ‘the least’ (25:40, 45) is the superlative form, also without exception in Matthew refers to disciples (10:42; 18:6, 10, 14; cf. also 5:19 and 11:11).
This makes the point of Jesus’ teaching closely parallel to Matthew 10:42: Jesus’ itinerant followers (today we might call them Christian missionaries) must be cared for by those to whom they minister. Affording material help to those who preach in the name of Jesus demonstrates acceptance of the missionaries’ message at the spiritual level . . . This view is almost certainly correct.
Today, however, the prevailing interpretation is that Jesus is teaching about the need to help the dispossessed whether or not they are Christian. . . .
This is obviously an important biblical theme, but is far less likely to be the focus of this particular passage, given the consistent meaning of the terms and the larger context of parables caring about the disciples (24:43–25:46).
— Craig L. Blomberg, Neither Poverty nor Riches: A Biblical Theology of Material Possessions, New Studies in Biblical Theology, ed. D. A. Carson (Downers Grove, IL: IVP, 2000), 126; my emphasis.