4 ὁ δὲ θεὸς πλούσιος ὢν ἐν ἐλέει, διὰ τὴν πολλὴν ἀγάπην αὐτοῦ
 God is rich in mercy because of his abundant love
ἣν ἠγάπησεν ἡμᾶς,
with which he loved us.
5 καὶ ὄντας ἡμᾶς νεκροὺς τοῖς παραπτώμασιν
 Although we were dead in our disobedience
συνεζωοποίησεν τῷ Χριστῷ,
he has made us alive together through Christ.
OR (I prefer the first option)
4 ὁ δὲ θεὸς πλούσιος ὢν ἐν ἐλέει, διὰ τὴν πολλὴν ἀγάπην αὐτοῦ … συνεζωοποίησεν τῷ Χριστῷ,
 God, who is rich in mercy because of his abundant love …, has made us alive together through Christ
…ἣν ἠγάπησεν ἡμᾶς,
…with which he loved us,
5 καὶ ὄντας ἡμᾶς νεκροὺς τοῖς παραπτώμασιν…
 even though we were dead in our disobedience, …
χάριτί ἐστε σεσῳσμένοι
You are saved by grace!
6 καὶ συνήγειρεν καὶ συνεκάθισεν ἐν τοῖς ἐπουρανίοις ἐν Χριστῷ Ἰησοῦ,
 God raised and sat us down in the heavenly places with Christ Jesus,
7 ἵνα ἐνδείξηται ἐν τοῖς αἰῶσιν τοῖς ἐπερχομένοις τὸ ὑπερβάλλον πλοῦτος τῆς χάριτος αὐτοῦ ἐν χρηστότητι ἐφʼ ἡμᾶς ἐν Χριστῷ Ἰησοῦ.
 so that in the coming ages he might show the unsurpassable riches of his grace through his generosity to us through Christ Jesus
These next four verses in chapter pick up directly from the previous verse. Verse four provides a contrast with verse three. On the one hand, we were children of wrath. But God is rich in mercy because of his abundant love. There is a rather important question regarding what Paul is intending to contrast. One might expect from the first three words, that the contrast would be between God and man. We were children of wrath, but God is perfect in his character. To some degree this is true. The focus of the first clause of verse four describes God’s attributes of mercy and love. It is exactly that God’s mercy stands is juxtaposition to sinful man that Paul intends to focus upon. In contrast to the children of wrath, God’s character allows for mercy and love as attributes. But in addition to this part of the contrast, there seems to be an implied element in verse three, “we were children of wrath [and thus do not deserve mercy] … but God is rich in mercy because of his abundant love…”
There are two syntactical options for translating verses four and five. One takes the participle “ὢν” as independent:” God is rich in mercy … he has made us alive in Christ.” The other views the “ὢν” as adjectival describing God: “God, who is rich in mercy … has made us alive in Christ.” The meaning is not substantially changed. Because there is some much distance between the subject, “God” and the verb, “has made us alive,” it is unclear which meaning is intended here. From a translational perspective, the English syntax is much more understandable in the first option. This would divide the section into two English sentences, putting a period before the “καὶ ὄντας ἡμᾶς νεκροὺς τοῖς παραπτώμασιν.”
There is also a good exegetical and syntactical reason for doing so as well. It seems quite likely that verse five intends to pick up the same thought as verse one, which also began a new sentence. Note the identical syntax of the two clauses: conjunction, copula participle, pronoun, accusative, dative. The only difference here is that now in verse four, Paul does not have the noun pair “τοῖς παραπτώμασιν καὶ ταῖς ἁμαρτίαις” in verse five.
The following clause, “- χάριτί ἐστε σεσῳσμένοι -” is a unique insertion on Paul’s part at this point. These words anticipate verses 8-10. Because of its interruptive nature, the purpose of this clause deserves some thought. Likely, Paul writes these words here as to summarize the point of Paul words so far. Before Christ, we were children of wrath; we were dead in our sins. It is only because of God’s rich mercy and love that he made us alive in Christ. It is by Grace that you are saved. But it is not only a summary, it is a declaration summary of God’s work through Christ, of his great mercy and love, working to save humanity. Most scholars & translations treat the phrase as a parenthetical comment, but generally I am cynical of such comments in Greek, particularly when the semantic relationships of the surrounding clauses could possibly be considered a sort of chiasm. Note the repetition of the “riches of grace/mercy” in verses 4 & 7 and the contrast of death and resurrection in verses 5 & 6.
Verse six expands verse five from “he has made us alive together in Christ” to “he raise and sat us down in the heavenly places with Christ.”
Finally, verse seven expresses the purpose of the previous few verses: God’s own glorification through his generous expression of abundant grace upon humanity through Christ Jesus.