ἐγώ

genitive ἐμοῦ, enclitic μου; dative ἐμοί, enclitic μοι; accusative ἐμέ, enclitic με; plural ἡμεῖς, etc.; personal pronoun,
I.
1. The nominatives ἐγώ and ἡμεῖς, when joined to a verb, generally have force and emphasis, or indicate antithesis, as Mt 3:11; Mk 1:8; Lk 3:16 (ἐγώ μέν... ὁ δέ); Mt 3:14 (ἐγώ... ἔχω, καί σύ); Mt 5:22, Mt 5:28, Mt 5:39, and often; ἡμεῖς, contrasted with God, Mt 6:12; ἡμεῖς καί οἱ Φαρισαῖοι, Mt 9:14; cf. Winer's Grammar, § 22, 6. But sometimes they are used where there is no emphasis or antithesis in them, as Mt 10:16; Jn 10:17; and in many editions in Mk 1:2; Lk 7:27; cf. Buttmann, § 129, 12. ἰδού ἐγώ, הִנֵּנִי, behold me, here am I: Acts 9:10 (1 Sam 3:8). ἐγώ, like אֲנִי, I am: Jn 1:23; Acts 7:32 (cf. Winers Grammar, 585 (544); Buttmann, 125 (109)).
2. The enclitic (and monosyllabic) genitive, dative, and accusative are connected with nouns, verbs, adverbs, but not with prepositions: ἔμπροσθεν μου, Jn 1:15; ὀπίσω μου, Mt 3:11; ἰσχυρότερός μου, ibid.; τίς μου ἥψατο, Mk 5:31; λέγει μοι, Rev 5:5; ἀρνήσηταί με, Mt 10:33; Lk 12:9 (on the accent in these expressions cf. Winers Grammar, § 6, 3; (Lipsius, Gram. Untersuch., p. 59ff; Lob. Path. Elementa ii., p. 323f; Tdf. N. T. edition 7, Proleg., p. 61f; edition 8, p. 104)); but δἰ ἐμοῦ, κατ' ἐμοῦ, πρό ἐμοῦ, etc., ἐν ἐμοί, περί, δἰ, ἐπ', κατ', εἰς ἐμέ. The only exception is πρός, to which the enclitic με is generally joined, Mt 25:36; Mk 9:19, and very often; very rarely πρός ἐμέ, Jn 6:37{a}, and according to L T Tr WH in Acts 22:8, Acts 22:13; Acts 24:19; (also Acts 23:22 T Tr WH; Jn 6:35 and 45 T Tr text WH; Lk 1:43 T WH; Mt 19:14; Jn 6:37{b},65, Tdf.; Jn 6:44 Tr text WH marginal reading; 1 Cor 16:11 L Tr; but πρός με, Mt 3:14 Tdf. and Mt 11:28 Griesbach; cf. Lipsius as above, p. 61 note). Moreover, the full forms ἐμοῦ, ἐμοί, ἐμέ are used in case of emphasis or antithesis; thus, ἐμοῦ, Lk 10:16; ἐμοί, Jn 7:23; Jn 10:38, etc.; ἐμέ, Mk 14:7; Jn 7:7, etc.
3. As in classic Greek, μου and ἡμῶν are very often used for the possessive pronouns ἐμός and ἡμέτερος (Buttmann, § 127, 21); and when so used,
a. they are generally placed after their substantives, as ὁ οἶκος μου, ἡ ζωή ἡμῶν, etc. — the fuller form ἐμοῦ only for the sake of distinction or antithesis (cf. Buttmann, § 127, 22), as μητέρα αὐτοῦ καί ἐμοῦ, Rom 16:13; πίστεως ὑμῶν τέ καί ἐμοῦ, Rom 1:12.
b. But they are sometimes placed before substantives, even which have the article, when no emphasis resides in the pronoun or antithesis is involved in its use (Winers Grammar, § 22, 7 N. 1; Buttmann, as above): μου τούς λόγους, Mt 7:24, Mt 7:26; even before prepositions, μου ὑπό τήν στέγην, Mt 8:8; less frequently ἡμῶν, as ἡμῶν τήν πόλιν, Acts 16:20; it is prefixed for emphasis in ἡμῶν τό πολίτευμα, Phm 3:20, cf. Winers Grammar, as above; Rost § 99, 4, p. 452ff 7th edition adduces a multitude of examples from Greek authors; (cf. Krüger, § 47, 9, 12 who states the rule as follows: when joined to a substantive having the article the reflexive genitive, with αὐτοῦipsius, and ἀλλήλων, requires the attributive position, the personal genitive, and αὐτοῦejus, the partitive position).
4. τί ἐμοί (ἡμῖν) καί σοι (ὑμῖν); what have I (we) to do with thee (you)? (cf. Buttmann, 138 (121); Winer's Grammar, 211 (198); 585 (544)): Mt 8:29; Mk 1:24; Mk 5:7; Lk 8:28; Jn 2:4; Heb. וָלָך מַה־לִּי, Judg 11:12; 2 Kgs 3:13; 2 Sam 16:10; 2 Chr 35:21; 2 Chr 35:1 Esdr. 1:24; also in classic Greek; cf. Aulus Gellius n. a. 1, 2; Epictetus diss. 2, 9, 16; τί ἡμῖν καί αὐτῷ, ibid. 1, 1, 16; τί ἐμοί καί αὐτοῖς, ibid. 1, 27, 13; 22, 15. τί γάρ μοι, what does it concern me? what have I to do etc.: 1 Cor 5:12; cf. Bos, Ellipses Graec., p. 599, Schaefer edition; Bernhardy (1829), p. 98; Krüger, § 48, 3, 9; Kühner, 2:364f; (Buttmann, as above, also 394 (337); Winers Grammar, 586 (545)).