13 “The kings of Tharsis and the isles shall offer gifts, the kings of the Arabians and of Saba shall lead presents”. This no longer requires an expounder but a thinker; yea it does thrust itself upon the sight not only of rejoicing believers, but also of groaning unbelievers— except perchance we must inquire why there has been said, “shall lead presents.” For there are wont to be led those things which can walk. For could it by any means have been spoken with reference to the sacrifice of victims? Far be it that such “righteousness” should arise in His days. But those gifts which have been foretold as to be led, seem to me to signify men, whom into the fellowship of the Church of Christ the authority of kings does lead: although even persecuting kings have led gifts, knowing not what they did, in sacrificing the holy Martyrs. “And there shall adore Him all kings of the earth, all nations shall serve Him”.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)