If I could pick a "life verse" from the writings of the Apostolic Fathers, it would have to be MPoly 9.1 (actually, MPoly 9.1a):

But as Polycarp entered the stadium, there came a voice from heaven: “Be strong, Polycarp, and act like a man.”
Michael William Holmes, The Apostolic Fathers : Greek Texts and English Translations (Updated ed.; Grand Rapids, Mich.: Baker Books, 1999), 233.

Τῷ δὲ Πολυκάρπῳ εἰσιόντι εἰς τὸ στάδιον φωνὴ ἐξ οὐρανοῦ ἐγένετο· Ἴσχυε, Πολύκαρπε, καὶ ἀνδρίζου.
Michael William Holmes, The Apostolic Fathers : Greek Texts and English Translations (Updated ed.; Grand Rapids, Mich.: Baker Books, 1999), 232.

Particularly, the portion spoken by the "voice from heaven", ἀνδρίζου. In BDAG, the headword is ἀνδρίζομαι; it is ἀνδρίζω in LSJ (why does BDAG do that?!). The word is also found in 1Co 16.13. Here's LSJ's relevant portion (sense II, not sense III):

II. make physically strong or manly, τοὺς γεωργοῦντας X.Oec.5.4.
2. endow with moral strength, Pl.Tht.151d; med., take courage, be resolute, X.An.4.3.34, Arist.EN1115b4, Lxx Jonah 1.6, 1Cor 16.13, D.C.50.24.7.

And here's BDAG:

conduct oneself in a courageous way w. κραταιοῦσθαι (like חֲזַק וֶאֱמָץ; cp. 2 Km 10:12; Ps 26:14; 30:25) 1 Cor 16:13; w. ἰσχύειν (Dt 31:6, 7, 23; Josh 1:6, 7 al.) MPol 9:1. ἀνδρίζου act like a man! Hv 1, 4, 3. Of an old man, whose hope in life has been renewed v 3, 12, 2. Also of a woman who is girded and of manly appearance v 3, 8, 4.

Why bring this up, and what am I thinking? My application is in the area of professional criticism. I've been doing some writing and I had to buck up to accept some fairly harsh criticism in order to review, revise and edit the writing for an article I'm hoping gets published (more on that at the appropriate time, perhaps). Instead of bristling and being defensive (my typical response in such situations) I need to stand, accept the criticism and react to it positively so that the end product can be better. In this case, it has become better, and is sure to become even better down the road.