5:15 βλέπετε οὖν ἀκριβῶς πῶς περιπατεῖτε μὴ ὡς ἄσοφοι ἀλλ’ ὡς σοφοί,
βλέπετε οὖν ἀκριβῶς – The particle οὖν is resumptive, i.e., “so then….” The verb is a present active imperative, indicating a warning. It is modified by the adverb ἀκριβῶς. Consider the textual variants with respect the ordering of ἀκριβῶς πῶς. Who is being addressed in the second person plural form?
πῶς περιπατεῖτε – An indirect question, marked by the interrogative adverb πῶς. The verb is present indicative and is the fifth usage of this verb introducing a hortatory section (4:1-16; 4:17-32; 5:1-5; 5:6-14; 5:15-6:9).
μὴ ὡς ἄσοφοι ἀλλ’ ὡς σοφοί — Two comparative clauses, one negative and one positive. Probably the verb περιπατέω is implied in both. The adjectives function as the subjects of the implied verbs. Note the use of the alpha-privative adjective ἄσοφος.
5:16 ἐξαγοραζόμενοι τὸν καιρόν, ὅτι αἱ ἡμέραι πονηραί εἰσιν.
ἐξαγοραζόμενοι τὸν καιρόν – An adverbial participle modifying either βλέπετε or περιπατεῖτε, but most likely the second. It is a middle participle and probably has the sense “buy up for yourself.” τὸν καιρόν is the direct object.
ὅτι αἱ ἡμέραι πονηραί εἰσιν – An adverbial causal clause, explaining why the action expressed in the participle is necessary. Note the connection between τὸν καιρόν and αἰ ἡμέραι. It is an equative clause with the subject marked by the article. What is the force of πονηρός when applied to a temporal concept?
5:17 διὰ τοῦτο μὴ γίνεσθε ἄφρονες, ἀλλὰ συνιέτε τί τὸ θέλημα τοῦ κυρίου.
διὰ τοῦτο μὴ γίνεσθε ἄφρονες – διὰ τοῦτο presumably refers to the ideas expressed in vv. 15-16 and draws an inference or conclusion, i.e., for this reason. The prohibition is expressed by μή + a present imperative. Does it have the sense “do not become foolish”? ἄφρονες is a predicate adjective. What is the relationship between ἄσοφος and ἄφρονες, another alpha-privative construction?
ἀλλὰ συνιέτε – The prohibition is followed by a positive command, which is intended to replace what is excluded. The imperative is present active and has the sense “comprehend, understand.”
τί τὸ θέλημα τοῦ κυρίου – An indirect question marked by the interrogative τί, which is a predicate nominative. This question is cast in the form of a nominal clause with the subject indicated by the arthrous noun τὸ θέλημα. τοῦ κυρίου is probably a subjective genitive. The clause functions as the object of συνιέτε.
5:18 καὶ μὴ μεθύσκεσθε οἴνῳ, ἐν ᾧ ἐστὶν ἀσωτία, ἀλλὰ πληροῦσθε ἐν πνεύματι,
καὶ μὴ μεθύσκεσθε οἴνῳ — Another prohibition, employing a present passive imperative. The verb means “become intoxicated.” οἴνῳ would be a dative of means.
ἐν ᾧ ἐστὶν ἀσωτία — ἐν may have a causal or resultative sense – by reason of which. The relative pronoun may reference the entire previous clause and not just οἴνῷ. ἀσωτία is the subject of ἐστὶν.
ἀλλὰ πληροῦσθε ἐν πνεύματι – Another negative…positive imperative structure marked by μή…ἀλλά with the second designed to replace the first. The verb is a present passive imperative. The adverbial prepositional phrase designates the means by which one “is filled.” Note the variation between οἴνῳ…ἐν πνεύματι (see Mark 1:8).
5:19 λαλοῦντες ἑαυτοῖς [ἐν] ψαλμοῖς καὶ ὕμνοις καὶ ᾠδαῖς πνευματικαῖς, ᾄδοντες καὶ ψάλλοντες τῇ καρδίᾳ ὑμῶν τῷ κυρίῳ,
λαλοῦντες ἑαυτοῖς – V. 19 continues the adversative clause begun in v. 18b with ἀλλὰ πληροῦσθε. λαλοῦντες is a present active participle functioning adverbially. Usually present participles describe action contemporary with that of the main verb. This participle relates its action to the plural subject. The participle may be resultative or temporal. The dative reflexive pronoun is the indirect object.
[ἐν] ψαλμοῖς καὶ ὕμνοις καὶ ᾠδαῖς πνευματικαῖς – Whether the preposition is original or not, these dative nouns probably describe the means by which this conversation occurs. Each of these nouns describes a poetic composition, usually set to music and often written for a religious purpose. The adjective πνευματικαῖς picks up the previous reference to ἐν πνεύματι. It is in the fourth attributive position (no article and following the noun). Does it modify all three nouns or only the one immediately preceding? See Col. 3:16.
ᾄδοντες καὶ ψάλλοντες τῇ καρδίᾳ ὑμῶν τῷ κυρίῳ — Two additional adverbial present participles modify πληροῦσθε, elaborating how these believers employed religious songs to enable the desired conversation. ᾄδω describes singing, usually with a note of praise. ψάλλω means to sing songs with or without musical accompaniment with the second dative expression marking the one for whom the singing occurs (τῷ κυρίῳ). Presumably these participles give further specification to the previous participle and have the same function in the clause. τῇ καρδίᾳ probably is a dative of manner describing how this singing is done, i.e., in a manner that is heart-felt; but it could be means, linking this activity with the Spirit.
5:20 εὐχαριστοῦντες πάντοτε ὑπὲρ πάντων ἐν ὀνόματι τοῦ κυρίου ἡμῶν Ἰησοῦ Χριστοῦ τῷ θεῷ καὶ πατρί.
εὐχαριστοῦντες πάντοτε ὑπὲρ πάντων – This is the fourth present participle in this series. The object of this thankful praise is identified in the dative case, i.e., the following τῷ θεῷ καὶ πατρί. Three adverbial elements qualify this participle. The first is the adverb πάντοτε which probably has a temporal sense – always, on every occasion. The second is the prepositional phrase ὑπὲρ πάντων which defines the things and/or people in reference to which thankful praise is offered. It is comprehensive. The word play is inclusive of time and circumstance.
ἐν ὀνόματι τοῦ κυρίου ἡμῶν Ἰησοῦ Χριστοῦ — This is the third adverbial modifier – another prepositional phrase. The preposition could indicate a locative idea or indicate under whose authority or warrant this thanksgiving is offered. Paul uses the full title of Jesus, but emphasizes his position as κύριος and then adds the appositional Ἰησοῦ Χριστοῦ. ἡμῶν is a genitive of subordination.
τῷ θεῷ καὶ πατρί — Dative complement of εὐχαριστοῦντες. This is an example of the Granville Sharp rule (TSKS), with both items referring to the same person.