Through Silvanus, our faithful brother, as I consider him, I have written to you briefly, exhorting, and testifying that this is the true grace of God in which you stand.
Exhorting, and testifying ...  Again, it is clear that "testifying" in apostolic times was not merely sounding off in public meetings, as the word is often understood today.  It was exhorting and commanding the people to obey the word of God.