Of whom the world was not worthy (hōn ouk ēn axios ho kosmos). Graphic picture in a short parenthetical relative clause (hōn, genitive plural with axios), a phrase to stir the blood of the readers.
Wandering (planōmenoi). Present middle participle of planaō, like lost sheep, hunted by wolves.
Caves (spēlaiois). Old word from speos (cavern) as in Mat 21:13.
Holes (opais). Old word, perhaps from ops (root of horaō, to see), opening, in N.T. only here and Jam 3:11. Cf. 1Ki 18:4; 2Macc 5:27; 10:6 (about Judas Maccabeus and others).