Ephesians 2:8-9 is probably on the Mt. Rushmore of Bible passages for American Evangelical Christians. BibleGateway.com once compiled the 100 most read Bible verses and Ephesians 2:8 came in 11th and 2:9 came in 28th (2:10 came in 37th). In my humble opinion, however, this passage is by and large misinterpreted.
Ephesians 2:8-9
For by grace you have been save through faith, and this is not your own doing; it is the gift of God--not the result of works, so that no one may boast.The topic of this blog concerns the meaning of "through faith". Most Evangelicals think this faith is our faith, but I will argue that the faith in question is Jesus' faithfulness, that is, Jesus' obedient death on the cross.
Strategy
I will first relate Ephesians 2:18 to 3:12. Then I will relate both to 2:8, while drawing on 2:13 and 16 and Colossians 1:20.
Ephesians 2:18 and 3:12
2:18: because through him we have the access
3:12: in whom we have boldness and access in confidence through the faith of(in) himIn both 2:18 and 3:12 access to the Father is mentioned and how Jesus made that happen. The grounds in 3:12 are already stated in the verse itself, it is "through the faith of(in) him". Now, I have purposely left the translation of "of(in)" vague so as not to prejudice the argument. It could mean our faith in Jesus, or it could mean Jesus' faith(fulness), that is, his obedience. However, it is when we determine the grounds for the access mentioned in 2:18 that I think everything falls into place for arguing that it is Jesus' faith(fulness).
Since 2:18 does not mention the grounds for access we have to look for it in the context. The best candidate seems to be 2:13: "But now in Christ Jesus you who were once far off have been brought near by the blood of Christ." The grounds of access here is "the blood of Christ". In 2:16, reconciliation in "through the cross". Colossians 1:20 has "and through him God was pleased to reconcile to himself all things, whether on earth or in heaven, by making peace through the blood of the cross." The argument from here is simple: the grounds of access simply have nothing to do with our faith but with Jesus' faithful death on the cross where he shed his blood.
Ephesians 2:8-9 revisited
The common language and themes shared between 2:8-9 and 3:12 and 2:18 argue strongly that we are saved by Jesus' faithful death on the cross and not by our faith. If it was our faith then why would 2:8 add "and this is not of yourselves"? If it was by our faith it would be of ourselves.
Theological Upshot
This discussion (which basically comes from Paul Foster) sheds light on the pistis Christou debate in Paul and argues for the subjective genitive. We are saved by something Jesus did, not by our faith. Our faith has a role, no doubt, but not in the way most evangelicals think.