It is typical to hear divine grace defined as "God's undeserved favor," but this does not capture the idea communicated here in Eph 2 or in other places in Paul. As this whole passage shows, God's grace, which is emphasized here by putting it first in the colon* (v. 8a), is actually God's favor granted to those who deserve his wrath (v. 3). It is not just undeserved, as if the people whom God befriends were neutral. It is act of immense favor bestowed on those who lie under God's just condemnation as transgressors and sinners. Hence, a better quick definition is: "God's favor despite human demerit."Ephesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 159–160.
Humans contribute nothing of their own to this salvation, since even believing (which the elect are indeed enabled to do) is a divine gift (cf. Rom 3:24–25). The key to this in the context of Eph 2:8 is what Paul had been driving home so forcefully up until now: Before God's gracious intervention believers were hopelessly dead, with their wills imprisoned by nature (φύσει, physei) in acts that led only to transgression and sin (2:1–5a, 12).
Ephesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 161.
The fallen condition of all humankind in Adam is not the result of mere social conditioning but is such "by nature" (φύσει, physei)Ephesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 152.
The main theme of Ephesians is easy to summarize with the phrase unity in the inaugurated new creation. Paul starts out teaching at some length on the church's unity as it is rooted in God's counsel and then in his redemptive accomplishment in the incarnate Son sealed to believers in the Holy Spirit. We see throughout Ephesians the rich, biblical teaching of a full and free salvation accomplished by the triune God and received by faith alone. But biblical faith is a living faith, which necessarily manifests its presence through loveEphesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 35
grace should be understood here and elsewhere in Paul as God's favor despite the demerits of its undeserving recipients. God forgives and imputes righteousness to those who had earlier rejected his rule as their Creator and treacherously fought against him.Ephesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 155
A devastating earthquake in AD 23 stunted the growth for a while, and the effects of Mark Antony's pillaging of the city also continued to cause the growth to be slow in the first half of the first century AD, when Paul was present in the cityEphesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 34
Writing in antiquity was a particularly arduous business. It was done while seated on the ground with the tablet or papyrus suspended on one's garment between crossed legs. The reed pen had to be sharpened just so and the ink made by hand. It is no wonder that secretaries (γραμματείς, grammateis) with specialized knowledge of the mechanics of writing were usually employed in drafting one's writingsEphesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 4
There are actually very few pseudepigraphical (forged) epistles from early Christianity (cf. comments on 6:21–24), but recent research has shown that there is reason to believe that the early church opposed this practice and would have been ready to reject Ephesians if it were suspicious
Ephesians, Evangelical Exegetical Commentary (Bellingham, WA: Lexham Press, 2015), 3.