Some commentators (for example, Vincent, Moule, Lohse; see New American Bible) take verse 21 to be the beginning of a new section, but it seems preferable to keep it (together with the closely related verse 22) as the conclusion of the main section, since there is no abrupt shift in subject matter.

As I write this would not be translated in such a way as to indicate that Paul was himself writing out the letter. It was obviously dictated since in verse 19 Paul specifically refers to something which he himself wrote as a part of the letter. Accordingly, one may translate as I write this as “as I send this letter to you.”

You will do what I ask translates “your obedience” (Revised Standard Version). Paul takes it for granted that Philemon will comply with his request to receive Onesimus back as he would receive Paul (verse 17).

But, Paul adds, I know that you will do even more. It would seem that Paul is thinking of the possibility that Philemon will set Onesimus free so that Onesimus can return to Paul and help him (verse 13). It may be necessary in some languages to indicate what is specifically involved in the comparison, for example, “I know that you will do even more than what I have asked you to do” or, as expressed in some languages, “I know that in what you will do you will surpass even what I have asked of you.”

Quoted with permission from Bratcher, Robert G. and Nida, Eugene A. A Handbook on Paul’s Letter to Philemon. (UBS Handbook Series). New York: UBS, 1977. For this and other handbooks for translators see here .