For ye have the poor with you always
 (See Gill on Matthew 26:11); 
 and whensoever ye will ye may do them good;
 by feeding them when hungry, clothing them when naked, and supplying them with the necessaries of life: 
 but me ye have not always;
 meaning, with respect to his bodily presence, which, in a short time, would be removed from them, and they would have no opportunity of showing him any such outward respect personally; (See Gill on Matthew 26:11).