16 “The King in truth,” is so written, because they chose a fox, a King in truth they would not have. “The King in truth:” that is, the true King, to whom the title was inscribed, when He suffered. For Pilate set this title inscribed over His Head, “The King of the Jews,” in the Hebrew, Greek, and Latin tongues: in order that all they that should pass by might read of the glory of the King, and the infamy of the Jews themselves, who, rejecting the true King, chose the fox Cæsar. “The King in truth shall rejoice in God.” They have been made portions of foxes....“Stopped up is the mouth of men speaking unjust things.” No one dares now openly to speak against Christ, now all men fear Christ. “For stopped up is the mouth of men speaking unjust things.” When in weakness the Lamb was, even foxes were bold against the Lamb. There conquered the Lion of the tribe of Judah, and the foxes were silenced.
Source: The Enarrations, or Expositions, on the Psalms (New Advent)