But he that is greatest among you
Either who really is so, having more grace, and greater gifts bestowed upon him, than others; which doubtless was the case of some of the disciples, or who desired to be the greatest, was ambitious of, and affected a superiority over others, and to be in the highest post and place, as it is certain some of them did. This was what they were often contending about among themselves, who should be greatest: and Christ here seems to have regard to that vain spirit, which appeared among them; and his view is, to check and restrain it: "shall be your servant"; or "let him be your servant". Service is the way to honour; he that would be most esteemed ought to do the most work; and the man that has the most grace, and the greatest gifts, ought to employ them for the use and benefit of others; (See Gill on Matthew 20:27).