But ye shall not be so,....See Gill on "Mt 20:26"but he that is greatest among you; in age or gifts, or would be thought to be the greatest, who is most ambitious of grandeur and authority, which perhaps might be Peter's case, who was the oldest man:let him be as the younger; as John, the beloved disciple, who was the youngest of them; and be as modest, and as humble as he, and reckon himself as in his place, and condescend to men of low estates, and esteem each other, even the youngest, better than himself.
So the phrase, aryezkyh abrkyh , "both greater and lesser", is used of the elder and younger.And he that is chief; that is, a spiritual ruler and governor in the church of God, as all the disciples were:as he that doth serve; for the apostles and ministers of the word, though they are over others in the Lord, and have the rule over them, yet they are servants for Jesus' sake, and so ought to reckon themselves; See Gill on "Mt 20:27".
Targum in 2 Chron. xxxi.