The previous context is very important to a proper understanding of Eph 2:8-10. Salvation by grace is defined as being made alive with Christ when we were dead. Despite what many claim, the best grammatical reading of the passage is that faith is the gift of God which is confirmed by such passages as Phil 1:29 and 2 Pet 1:1. With salvation there is no room for human boasting for we come to Christ with empty hands.