εὐχαριστέω, εὐχαριστῶ; 1 aorist ἐυχαρίστησα (Act 27:35) and ἠυχαρίστησα (Rom 1:21 G L T Tr WH; see references in εὐδοκέω, at the beginning); 1 aorist passive subjunctive 3 person singular εὐχαριστηθῇ (2Co 1:11); (εὐχάριστος, which see);

1. to be grateful, feel thankful; so in the decree of the Byzantines in Demosthenes pro cor., p. 257, 2.

2. to give thanks (so Posid. quoted in Athen. 5, p. 213 e.; Polybius, Diodorus, Philo, Josephus, Plutarch, Epictetus, others; cf. Lob. ad Phryn., p. 18 (Winer’s Grammar, 23 (22))): τίνι, especially τῷ Θεῷ, Luk 17:16; Act 27:35; Act 28:15; Rom 14:6; Rom 16:4; 1Co 14:18 (see below); Php 1:3; Col 1:3; Col 1:12; Phm 1:4; (with the accusative (hence, as the nominative) in the passive, ἵνα ... ὑπέρ τῶν ἀγαθῶν ὁ Θεός ἐυχαρίστηται, Philo, quis rer. div. her. § 36). simply, so that τῷ Θεῷ must be added mentally: Rom 1:21; (1Co 14:17); 1Th 5:18; especially where the giving of thanks customary at the beginning of a feast, or in general before eating, is spoken of: Mat 15:30; Mat 26:27; Mar 8:6; Mar 14:23; Luk 22:17; Luk 22:19; Joh 6:11; Joh 6:23; 1Co 11:24; εὐχαριστεῖν τῷ Θεῷ διά Ἰησοῦ Χριστοῦ, through Christ i. e. by Christ’s help (because both the favors for which thanks are given and the gratitude which prompts the thanks are due to Christ (cf. Winer’s Grammar, 378 (354) note)): Rom 1:8; Rom 7:2.) R WH marginal reading; Col 3:17; τῷ Θεῷ ἐν ὀνόματι Χριστοῦ (see ὄνομα, 2 c.), Eph 5:20. Of that for or on account of which thanks are given to God, we find — περί τίνος, the genitive of person, concerning, with regard to one (1Th 1:2); 2Th 1:3 (cf. Ellicott, in the place cited); with ὅτι added epexegetically, Rom 1:8 (where R G ὑπέρ); 2Th 2:13; with addition of ἐπί and the dative of the thing for, on account of, which, 1Co 1:4; ὑπέρ τίνος, the genitive of person, Eph 1:16; ὑπέρ with the genitive of the thing, for, on account of, 1Co 10:30; Eph 5:20; the matter or ground of the thanksgiving is expressed by a following ὅτι: Luk 18:11; Joh 11:41; 1Co 1:14; 1Th 2:13; Rev 11:17; or is added asyndetically without ὅτι, 1Co 14:18 (λαλῶ L T Tr WH, for which R G λαλῶν, the participle declaring the cause which prompts to thanksgiving (Winers Grammar, 345f (324); Buttmann, 300 (258))). Once εὐχαριστεῖν τί, for a thing, in the passage 2Co 1:11 (cf. Buttmann, 148 (130); Winer’s Grammar, 222 (209)); in the Fathers εὐχαριστεῖν τί is "to consecrate a thing by giving thanks, to ’bless’": ὁ ἐυχαριστηθεις ἄρτος καί οἶνος, Justin Martyr, Apology 1, 65 at the end; ἐυχαριστηθεισα τροφή, ibid.

c. 66; εἰσιν οἱ ἐυχαριστουσι ψιλον ὕδωρ, Clement of Alexandria, strom. i., p. 317, Sylb. edition; (cf. Suicer, Thesaurus i., 1269. "The words εὐχάριστος, εὐχαριστεῖν, εὐχαριστία, occur in St. Paul’s writings alone of the apostolic Epistles" (Lightfoot; cf. Ellicott on Col 1:12)).