ἀγαθός, -ή, -όν, (akin to ἄγαμαι to wonder at, think highly of, ἀγαστός admirable, as explained by Plato, Crat., p. 412 c. [others besides; cf. Donaldson, New Crat. § 323]), in general denotes "perfectus,... qui habet in se ac facit omnia quae habere et facere debet pro notione nominis, officio ac lege" (Irmisch ad Herodian, 1, 4, p. 134), excelling in any respect, distinguished, good. It can be predicated of persons, things, conditions, qualities and affections of the soul, deeds, times and seasons. To this general significance can be traced back all those senses which the word gathers from the connection in which it stands;
1. of a good constitution or nature: γῆ, Luke 8:8; δένδρον, Matthew 7:18, in sense equivalent to 'fertile soil,' 'a fruitful tree,' (Xenophon, oec. 16, 7 γῆ ἀγαθή,... γῆ κακῇ, an. 2, 4, 22 χώρας πολλῆς καί ἀγαθῆς οὔσης). In Luke 8:15 ἀγαθή καρδία corresponds to the figurative expression 'good ground', and denotes a soul inclined to goodness, and accordingly eager to learn saving truth and ready to bear the fruits (καρπούς ἀγαθούς, James 3:17) of a Christian life.
2. useful, salutary: δόσις ἀγαθή (joined to δώρημα τέλειον) a gift which is truly a gift, salutary, James 1:17; δόματα ἀγαθά, Matthew 7:11; ἐντολή ἀγαθός a commandment profitable to those who keep it, Romans 7:12, according to a Greek scholium equivalent to εἰς τό συμφέρον ἐισηγουμένη, hence, the question in Romans 7:13: τό οὖν ἀγαθόν ἐμοί γέγονε θάνατος; ἀγαθός μερίς the 'good part,' which insures salvation to him who chooses it, Luke 10:42; ἔργον ἀγαθόν (differently in Romans 2:7, etc.) the saving work of God, i. e. substantially, the Christian life, due to divine efficiency, Philippians 1:6 [cf. the commentaries at the passage]; εἰς ἀγαθόν for good, to advantage, Romans 8:28 (Sir. 7:13; πάντα τοῖς ἐυσεβέσι εἰς ἀγαθά... τοῖς ἁμαρτωλοῖς εἰς κακά, Sir. 39:27; τό κακόν... γίγνεται εἰς ἀγαθόν, Theognis 162); good for, suited to something: πρός οἰκοδομήν, Ephesians 4:29 [cf. Winers Grammar, 363 (340)] (Xenophon, mem. 4, 6, 10).
3. of the feeling awakened by what is good, pleasant, agreeable, joyful, happy: ἡμέραι ἀγαθάς 1 Peter 3:10 (Psalm 33:13 (Ps. 34:13); Sir. 14:14; 1 Macc. 10:55); ἐλπίς, 2 Thessalonians 2:16 (μακαρία ἐλπίς, Titus 2:13); συνείδησις, a peaceful conscience, equivalent to consciousness of rectitude, Acts 23:1; 1 Timothy 1:5, 19; 1 Peter 3:16; reconciled to God, 1 Peter 3:21.
4. excellent, distinguished: so τί ἀγαθόν, John 1:46 (John 1:47).
5. upright, honorable: Matthew 12:34; Matthew 19:16; Luke 6:45; Acts 11:24; 1 Peter 3:11, etc.; πονηροί καί ἀγαθοί, Matthew 5:45; Matthew 22:10; ἀγαθός καί δίκαιος, Luke 23:50; καρδία ἀγαθή καί καλή, Luke 8:15 (see καλός, b.); fulfilling the duty or service demanded, δοῦλε ἀγαθέ καί πιστέ, Matthew 25:21, 23; upright, free from guile, particularly from a desire to corrupt the people, John 7:12; preeminently of God, as consummately and essentially good, Matthew 19:17 (Mark 10:18; Luke 18:19); ἀγαθός θησαυρός in Matthew 12:35; Luke 6:45 denotes the soul considered as the repository of pure thoughts which are brought forth in speech; πίστις ἀγαθός the fidelity due from a servant to his master, Titus 2:10 [WH marginal reading omits]; on ἀγαθόν ἔργον, ἀγαθά ἔργα, see ἔργον. In a narrower sense, benevolent, kind, generous: Matthew 20:15; 1 Peter 2:18; μνεία, 1 Thessalonians 3:6 (cf. 2 Macc. 7:20); beneficent (Xenophon, Cyril 3, 3, 4; טוב, Jeremiah 33:11; Psalm 34:9; Cicero, nat. deor. 2, 25, 64 "optimus i. e. beneficentissimus), Romans 5:7, where the meaning is, Hardly for an innocent man does one encounter death; for if he even dares hazard his life for another, he does so for a benefactor (one from whom he has received favors); cf. Winer's Grammar, 117 (111); [Gifford in the Speaker's Commentary, p. 123].
The neuter used substantively denotes:
1. a good thing, convenience, advantage, and in partic.
a. in the plural, external goods, riches: Luke 1:53; Luke 12:18f. (Sir. 14:4; Wis. 7:11); τά ἀγαθά σου comforts and delights which thy wealth procured for thee in abundance, Luke 16:25 (opposed to κακά, as in Sir. 11:14); outward and inward good things, Galatians 6:6, cf. Wieseler at the passage.
b. the benefits of the Messianic kingdom: Romans 10:15; τά μέλλοντα ἀγαθῶν, Hebrews 9:11; Hebrews 10:1.
2. what is upright, honorable, and acceptable to God: Romans 12:2; ἐργάζεσθαι τό ἀγαθόν Romans 2:10; Ephesians 4:28; πράσσειν, Romans 9:11; (2 Corinthians 5:10); διώκειν, 1 Thessalonians 5:15; μιμεῖσθαι, 3 John 1:11; κολλᾶσθαι τῷ ἀγαθῷ Romans 12:9; τί με ἐρωτᾷς περί τοῦ ἀγαθοῦ, Matthew 19:17 G L T Tr WH, where the word expresses the general idea of right. Specifically, what is salutary, suited to the course of human affairs: in the phrase διάκονος εἰς τό ἀγαθόν Romans 13:4; of rendering service, Galatians 6:10; Romans 12:21; τό ἀγαθόν σου the favor thou conferrest, Philemon 1:14.

BLB Scripture Index of Thayer's