Strong's Concordance
Definition: adv. (a) of time: just now, even now; just at hand, immediately,
(b) of logical connection: now then, (c) in commands and appeals: at this instant.
Thayer's Greek Lexicon
νυνί; (νῦν with iota demonstrative (Krüger, § 25, 6, 4f; Kühner, § 180, e. (Jelf, § 160, e.); Alexander Buttmann (1873) Gram. § 80, 2)), in Attic note, at this very moment (precisely now, neither before nor after; Latinnunc ipsum), and only of Time, almost always with the present, very rarely with the future (cf. Lob. ad Phryn., p. 19). Not found in the N. T. except in the writings of Paul and in a few places in Acts and the Epistle to the Hebrews; and it differs here in no respect from the simple νῦν; cf. Fritzsche, Romans, i., p. 182; (Winer's Grammar, 23);
1. of Time: with a present (Job 30:9), Acts 24:13 L T Tr WH; Romans 15:23, 25; 1 Corinthians 13:13 (ἄρτι ... τότε δέ ... νυνί δέ); 2 Corinthians 8:11, 22; Philemon 1:9, 11 (namely, ὄντα); with a perfect indicating continuance, Romans 3:21 (others refer this to 2); with a preterite (Psalm 16:11 ()), Romans 6:22 (opposed to τότε); Romans 7:6; Ephesians 2:13 (opposed to 1, τῷ καιρῷ ἐκείνῳ); Colossians 1:22 () (and Colossians 3:8; also Romans 11:30 WH marginal reading) (opposed to πότε); Colossians 1:26 (R G L marginal reading; cf. Winers Grammar, § 63 I. 2 b.; Buttmann, 382 (328)) (opposed to ἀπό τῶν αἰώνων); with a future, Job 7:21; Baruch 6:4 (Epistle Jeremiah 3); 2 Macc. 10:10; τῆς πρός ὑμᾶς νυνί ἀπολογίας, Acts 22:1.
2. contrary to Greek usage, in stating a conclusion (see νῦν, 2), but since the case stands thus (as it is): 1 Cor. ( R G T L marginal reading); R G (i. e. since ὁ γλώσσῃ λαλῶν without an interpretation cannot edify the church); but now (German so aber), Hebrews 9:26 L T Tr WH; after a conditional statement with εἰ (see νῦν, at the end), Romans 7:17; 1 Corinthians 12:18 (R G T WH marginal reading); ; Hebrews 8:6 (here L Tr marginal reading WH text νῦν), cf. ; Rec., cf. ; (Buttmann, § 151, 26).
BDAG Lexicon:
νυνί
νυνί adv. of time (Hdt. 7, 229 al.; SIG 259, 11 [338/337 B.C.]; PPetr III, 42 H [8] f, 4 [III B.C.]; POxy 490, 5 [124 A.D.]; 506, 25; 908, 5; LXX [Thackeray 191]; TestJob; JosAs cod. A 12, 7; 13, 5 [p. 55, 15; 57, 12 Bat.]; Joseph.; Ar. 13, 7; Just., D. 11, 2; Tat. 28, 1) an emphatic form of νῦν made by adding to it the demonstrative suffix ι (Kühner-Bl. I 620; B-D-F §64, 2; Rob. 296; 523) without alteration of mng. (Mayser 456). Except for Ac 22:1 v.l.; 24:13; Hb 8:6;9:26; 11:16 v.l.; ἐπεὶ δὲ ν̣υ̣ν̣ί̣ AcPt Ox 849; 1 Cl 47:5; 2 Cl 2:3, only in the Pauline writings and there always ν. δέ (the ms. tradition oft. varies betw. νῦν and νυνί)
① temporal marker with focus on the moment as such, now
ⓐ w. the pres. (Job 30:9; Jos., Ant. 14, 404) Ac 24:13; Ro 15:23, 25; 2 Cor 8:22; Phlm 9; cp.11; perh. also AcPt Ox 849.
ⓑ w. the perf. in pres. sense ν. δὲ … πεφανέρωται but now … has been revealed Ro 3:21.
ⓒ w. aor. (Job 30:1; Just., D. 11, 2) Ro 6:22; 7:6; 11:30 v.l.; Eph 2:13; Col 1:22; 2 Cl 2:3. Impv.: 2 Cor 8:11; Col 3:8; 1 Cl 47:5.
ⓓ w. a subst. (PRyl 111, 4 [161 A.D.] τὴν νυνεὶ γυναῖκά μου) ἡ πρὸς ὑμᾶς ν. ἀπολογία the defense which I now make before you Ac 22:1.
② temporal marker with focus on a prevailing situation, w. the idea of time weakened or entirely absent, now, as it is
ⓐ ν. δέ but now, as the situation is Ro 7:17; 1 Cor 13:13; 14:6 v.l. (Tat. 28, 1).
ⓑ introducing the real situation after an unreal conditional clause or sentence but, as a matter of fact 1 Cor 5:11 v.l.; 12:18; 15:20; Hb 8:6; 9:26; 11:16 v.l.—DELG s.v. νυ. M-M.
First Corinthians: A New Translation with Introduction and Commentary
By Joseph A. Fitzmyer
13. And now faith, hope, love remain, these three. So Paul draws his description of love to a close, with a verse that has many problems, not the least of which is the connection of the threesome to what has immediately preceded in vv. 10-12 and the addition of faith and hope to a discussion that has involved so far only love. It is a formula that is meant to terminate the discussion of love and its relation to the pneumatika, but it introduces a further discussion of two of them; and its wording raises a number of questions.
One thing is clear, however, pistis is not the same as that in v. 2, "faith to move mountains"; rather it now denotes the full sense of saving and justifying "faith," the response to the Christian gospel, as in other Pauline passages (Rom 10:6-10: belief in the death and resurrection of Christ Jesus), and especially in those in which the triad further occurs (l Thess 1:3; 5:8; Gal 5:5—6; cf. Col 1:4-5). Note also the linking of love to faith in 1 Cor 16:13-14; Thess 3:6; Phlm 5. The triad, however, is meant to replace the threesome of tongues, prophecy, and knowledge of vv. 1-2 and 8.
The first difficulty is the meaning of the adv. nyni, "now." It is scarcely to be understood as the equivalent of the temporal adv. arti (v. 12a), which was contrasted with tole, "then," another adv. of time. It is rather expressing a logical conclusion, as in Rom 7:17: “but now,” i.e., as the situation is (BDAC, 682). Cf. also il Cor 12:18; 15:20; 2 Cor 8:11, l2.