In Matthew 25:35-40
Jesus said "I was sick, and ye visited me: I was in prison, and ye came unto me. Then shall the righteous answer him, saying, Lord, when saw we thee an hungered, and fed thee? Or thirsty, and gave thee drink? When saw we thee a stranger, and took thee in? Or naked and clothed thee? And the King shall answer and say unto them, Verily I say unto you, inasmuch as ye have done it unto on of the least of these my brethren, ye have done it unto me."