Thematic Relation: Here, there is a direct appeal to persevere in well-doing. Another who has done so is held to the light not only as an example to follow, but also as an encouragement in that it shows Gaius that he is not alone.
Paraphrase
11 Having examples of good and evil, follow the good for it is of God. Evildoers don't see God. 12 Demetrius is a good example, as many including John testify to.
Key Verse
11 - It holds the point that there is a clear distinction between good and evil.
New Thoughts
How do we recognize true witness? How do we discern the true teacher from the false? It seems to me that the 'know' of this verse offers a key: we perceive with the senses, we inspect and examine what is being said or taught. If we have already acquainted ourselves with, and become skilled at the truth, then we will see this new thing and know whether it accords with the truth we know or stands in opposition to it. So the key is twofold. First, we must prepare ourselves by attention to the truth we have. This comes primarily of prayerful study of the Bible itself, and is augmented by the teaching of trusted teachers. Thus prepared, we are in position to examine every new thing. If it accords, and we find this particular source consistently accords with the truth, then we have established another trusted teacher. If not, then we ought to avoid any potential influencing by this new source. The strictures of 2 John apply to such a one, and we ought - as far as possible - to break contact with this person, lest we join them in their falsehood.