Ephesians 2:8-10 (NKJV)
For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, lest anyone should boast. For we are His workmanship, created in Christ Jesus for good works, which God prepared beforehand that we should walk in them.
I don't believe I have ever shared my faith without quoting this verse. It is packed with good theology. Grace is unmerited favor from God. Salvation starts with Him. Faith is the channel through which God's grace is received. Faith is hands and heart opening to receive God's gift of salvation. Faith is trusting in Christ alone for eternal life and not in yourself or in some other person.
In the above verse it is not clear as to what the gift refers to, does it refer to salvation or does it refer to faith. I don't think it matters because I believe that it is phrased that way to indicate that grace, salvation and faith are all a gift of God. But faith is our part of the equation right? Yes, just like reaching out to accept a gift offered to you is your part. You can refuse to accept it which would be rude, or badness on your part, making you responsible. But in no way does your act of receiving a gift indicate any goodness on your part. The analogy stops there because faith goes further than just accepting a gift. Saving faith means rejecting any other form of salvation that humans will conjure up such as any sort of works-based religion. I find it interesting that every other religion besides Christianity is based on some sort of works to be performed to get to heaven. In other words, the grace of God is not found in any other religion.
Now after having disparaged works, does this mean that there are no works in Christianity? Not at all. In fact, Christianity has works and they are even meritorious...but not for salvation. We don't even get to choose which ones we do. The verse says God has prepared them beforehand. We were made for God's pleasure and for his service.