Νῦν now is logical: as the case now stands. For ὀρέγονται desire, see on 1Ti 3:1.
Is not ashamed (οὐκ ἐπαισχύνεται)
Because they have commended themselves to God by their faith, so that he acknowledges them as his own. Comp. Heb 2:11; Mar 8:28, Mar 8:38; Rom 1:16; 2Ti 1:8, 2Ti 1:16.
To be called their God (Θεὸς ἐπικαλεῖσθαι αὐτῶν)
Lit. to be surnamed. Comp. Act 4:36; Act 10:5, Act 10:18, Act 10:32. God was called the God of Abraham, of Isaac, and of Jacob. See Exo 3:6.
For he hath prepared for them a city (ἡτοίμασιν γὰρ αὐτοῖς πόλιν)
Comp. Mat 25:34; Joh 14:2; Rev 21:2. City is significant, as showing that the fulfillment of God's promise lies in introducing them into the perfection of social life. Comp. Rev 3:12; Rev 21:2, Rev 21:10; Rev 22:19.