Albert Barnes Commentary Matthew 25:40

"And the King shall answer and say unto them, Verily I say unto you, Inasmuch as ye did it unto one of these my brethren, [even] these least, ye did it unto me." — Matthew 25:40 (ASV)

One of the least of these. One of the obscurest, least known, poorest, and most despised and afflicted.

My brethren. Either those who are Christians, whom he condescends to call brethren, or those who are afflicted, poor, and persecuted, who are his brethren and companions in suffering, and who suffer as he did on earth. See Hebrews 2:11; Matthew 12:50. How great is the condescension and kindness of the Judge of the world, thus to reward our actions, and to consider what we have done to the poor as done to him!