Although St. Paul is the undisputed author of this epistle, the above verse is an interesting addition written by a man named Tertius, who served as the disciple’s secretary or “amanuensis” (assistant).
Like many of us who have a secretary, Paul apparently liked to dictate his letters –allowing the spirit to move him freely while someone else transcribed what was spoken. Near the conclusion he would normally pen a small greeting in his own handwriting which served as a token of the letter’s authenticity; but here he allows Tertius to speak for himself and record his own greeting for posterity.
Another reason why St. Paul may have used a secretary was because he suffered a type of eye ailment which forced him to use rather large lettering when he did write; perhaps something akin to John Hancock’s large writing style. Mention of this is made in Paul’s letter to the Galatians: “See with what large letters I am writing to you with my own hand.” (6:11)
