Diotrephes or Demetrius
Do not, friend, imitate the bad, but the good. The well-doer is from God; the wrong-doer has not seen God. (3 John 11 - 1901 Holy Bible in Modern English)
If you've read this verse in other English versions of the bible, It reads very different. I've checked many of them, and they speak of "the person" or "He" who does good vs evil or some variation of that. This version captures a concept lost in most of the English translations that was present in the Greek. The Good isn't exactly declared to be a person in the Greek versions.
Note that we are to imitate the good, not the bad.
Then note that the good is from God (FROM, not WITH, OF or FOR.)
Then note that the wrong-doer is anyone (everyone) who has not seen God.
This subject is covered many other places, but here is summed up in one clear statement. As Christians, we are not to imitate people (even "good" people.) We should seek to imitate the one God sent to save us. If you look at the Greek translation it is clear that the original text is saying not to imitate any person, but Christ himself.
Paul speaks the same subject in Galations 1, and Jesus spoke the same message throughout his ministry.