Bear with (anechesthe). Present middle imperative (some MSS. have anechesthai, infinitive) of anechō with the ablative, “hold yourselves back from” as in Col 3:13.
The word of exhortation (tou logou tēs paraklēseōs). His description of the entire Epistle. It certainly is that, a powerful appeal in fact.
I have written (epesteila). First aorist active indicative (epistolary aorist) of epistellō, old word to send a letter (epistolē) as in Act 15:20.
In few words (dia bracheōn). Common Greek idiom, here only in N.T. (from brachus, brief, short). Cf. di' oligōn egrapsa in 1Pe 5:12.