3 John 1:1-4
No greater joy than to hear my children walk in truth
1The elder to Gaius the beloved, whom I love in truth.
2Beloved, I pray that you may prosper in all things and be healthy, even as your soul prospers.
3For I rejoiced greatly, when brothers came and testified about your truth, even as you walk in truth.
4I have no greater joy than this, to hear about my children walking in truth.
The report that reaches the elder is about how Gaius walks, not what he holds. Others testified to it, which makes the proof of C12 something observed by third parties rather than claimed by the man himself.
3 John 1:5-8
A faithful work for brothers and strangers
5Beloved, you do a faithful work in whatever you accomplish for those who are brothers and strangers.
6They have testified about your love before the assembly. You will do well to send them forward on their journey in a way worthy of God,
7because for the sake of the Name they went out, taking nothing from the Gentiles.
8We therefore ought to receive such, that we may be fellow workers for the truth.
Resources given to travellers who are strangers, who took nothing from the Gentiles and so have no other support. Habitual Almsgiving directed at the stranger by name, and the sending forward is to be done in a manner worthy of God rather than merely adequate.
3 John 1:9-10
Diotrephes, who loves to be first
9I wrote to the assembly, but Diotrephes, who loves to be first among them, doesn’t accept what we say.
10Therefore, if I come, I will call attention to his deeds which he does, unjustly accusing us with wicked words. Not content with this, neither does he himself receive the brothers, and those who would, he forbids and throws out of the assembly.
The charge is a disposition and its consequences, in that order: he loves to be first, and therefore refuses the brothers and expels anyone who would receive them. The Hidden Life shown by its absence — a man whose faithfulness has to be visible ends by controlling who else may be faithful.
3 John 1:11-12
Don't imitate evil, but good; Demetrius has the testimony of all
11Beloved, don’t imitate that which is evil, but that which is good. He who does good is of God. He who does evil hasn’t seen God.
12Demetrius has the testimony of all, and of the truth itself; yes, we also testify, and you know that our testimony is true.
Two named men set side by side and judged entirely by conduct, with Demetrius commended on the testimony of all rather than on office or teaching. The fruit test of C08 applied to people the readers actually knew, which is the form in which it is hardest to apply.
3 John 1:13-14
Greet the friends by name
13I had many things to write to you, but I am unwilling to write to you with ink and pen;
14but I hope to see you soon, and we will speak face to face. Peace be to you. The friends greet you. Greet the friends by name.
The canon's shortest book ends by asking that greetings be delivered individually rather than to the group. The Sacrament of the Ordinary in its plainest form: the last instruction in this correspondence is to say hello to people one at a time.