Note 17 at Col. 4:18: Paul usually wrote his letters with the aid of a secretary. For instance, in Romans his secretary was Tertius (Rom. 16:22). After each letter Paul would personally sign the letter as he does here. This signature authenticated the letter and made it harder for forgeries to be passed in Paul's name.

Note 18 at Col. 4:18: As mentioned in the INTRODUCTION TO THE EPISTLE OF PAUL TO THE PHILLIPIANS, p. 1148, Paul was not complaining about his imprisonment. He rejoiced more in his prison epistles than in his other writings. He isn't complaining now either. However, we can see from this three-word sentence that there were difficulties associated with imprisonment and Paul requested prayer.