In some discussions earlier this year, Steve Hays was criticized for seeing the brothers mentioned in Matthew 25:40 as Christians rather than people in general. He was called a "cretin", accused of having a "lack of moral compass", said to be engaging in "eisegesis", etc.
As Steve has noted before, Craig Blomberg refers to Steve's view as one that was the majority position in previous generations, but has become a minority view lately (Matthew [Nashville, Tennessee: Broadman Press, 1992], p. 378). I recently read Jerome's commentary on Matthew, written in the late fourth century, and here's what he had to say on this subject:
"As for the words that follow: 'When you did it to one of the least of these brothers of mine, you did it to me,' it does not seem to me that he said this generally of the poor, but of those who are poor in spirit. For it was to them that he reached out his hand and said: 'My brothers and my mother are those who do the will of my Father.'" (Thomas Scheck, trans., St. Jerome: Commentary On Matthew [Washington, D.C.: The Catholic University Of America Press, 2008], p. 290)