Extended Strong's Greek Lexicon (Abbott-Smith based)
if also
Usage: εἰ, conjunctive particle, used in conditions and in indirect questions. __I. Conditional, if; __1. with indic, expressing a general assumption; __(a) pres.: before indic, pres., Mat.11:14, Rom.8:25, al.; before imperat., Mrk.4:23 9:22, Jhn.15:18, 1Co.7:9, al.; before fut. indic., Luk.16:31, Rom.8:11, al.; before pf. or aor., with negation in apodosis, Mat.12:26, Rom.4:14, al.; similarly, before impf., Luk.17:6, Jhn.8:39; before quæst., Mat.6:23, Jhn.5:47 7:23 8:46, 1Pe.2:20; __(b) fut.: Mat.26:33, 1Pe.2:20;
__(with) pf.: Jhn.11:12, Rom.6:5, al.; __(d) aor.: Luk.16:11 19:8, Jhn.13:32, 18:23, Rev.20:15, al. __2. Where the assumption is certain = ἐπεί: Mat.12:28, Jhn.7:4, Rom.5:17, al. __3. Of an unfulfilled condition, with indic, impf., aor. or plpf., before ἄν, with imp. or aor. (see: ἄν, I, i). __4. C. indic., after verbs denoting wonder, etc., sometimes, but not always, coupled with an element of doubt: Mrk.15:44, 1Jn.3:13, al. __5. C. indic., as in LXX (Num.14:3o, 1Ki.14:45, al. = Heb.
אִם), in oaths, with the formula of imprecation understood in a suppressed apodosis (WM, 627; Burton, §272): Mrk.8:12, Heb.3:11" (LXX) 4:3 (LXX). __6. Rarely (cl.) with optative, to express a merely possible condition: Act.24:19 27:39, 1Co.14:10 15:37, I Pe3:14, 17. __II. Interrogative, if, whether. __1. As in cl., in indir. questions after verbs of seeing, asking, knowing, saying, etc.: with indic. pres., Mat.26:63, Mrk.15:36, Act.19:2, 2Co.13:5, al.; fut., Mrk.3:2, Act.8:22, al.; aor., Mrk.15:44, 1Co.1:16, al.;
with subjc. aor. (M, Pr., 194), Php.3:12. __2. As in LXX (= Heb. אִם and interrog. הֲ, Gen.17:17, al.; see WM, 639f.; Viteau, i, 22), in direct questions: Mrk.8:23 (Tr., WH, txt.), Luk.13:23, 22:49, Act.19:2, al. __III. With other particles. __1. εἰ ἄρα, εἴγε, εἰ δὲ μήγε, see: ἄρα, γε. __2. εἰ δὲ καί, but if also: Luk.11:18; but even if, 1Co.4:7, 2Co.4:3 11:16. __3. εἰ δὲ μή, but if not, but if otherwise: Mrk.2:21, 22 Jhn.14:2, Rev.2:5, al. __4.
εἰ καί, if even, if also, although: Mrk.14:29, Luk.11:8, 1Co.7:21, 2Co.4:16, Php.2:17, al. __5. καὶ εἰ, even if, see: καί __6. εἰ μή, if not, unless, except, but only: Mat.24:22, Mrk.2:26 6:5, Jhn.9:33, 1Co.7:17 (only), Gal.1:19 (cf. ἐὰν μή, 2:16; see Hort., Ja., xvi); ἐκτὸς εἰ μή, pleonastic (Bl., §65, 6), 1Co.14:5 15:2, 1Ti.5:19. __7. εἰ μήν = cl. ἦ μήν (M, Pr., 46), in oaths, surely (Eze.33:27, al.): Heb.6:14. __8. εἴ πως, if haply: Act.27:12, Rom.1:10. __9. εἴτε . . . εἴτε, whether . . . or;
Rom.12:6-8, 1Co.3:22 13:8, al. (AS)