Ephesians 2:8-9 - Faith: Where does it come from?

Ephesians 2:8-9 reads: "For it is by grace you have been saved, through faith--and this not from yourselves, it is the gift of God - not by works, so that no one can boast." However, this translation is ambiguous. Is it saying that "faith" is a gift of God? Or is the concept of salvation by grace through faith, the gift of God? What does "this" refer to? The Greek syntax and grammar make it almost impossible for this verse to be interpreted as saying that faith is a gift from God. In addition, an analysis of the verse structure also rules out this interpretation. The clause "not from yourselves, it is the gift of God" is parallel to "not by works, so that no one can boast." Now, if "this" refers to faith, we would have: "and this faith is not from yourselves, it is the gift of God" and "this faith is not by works, so that no one can boast" which is tautology (ie. stating the obvious - in this case, it is blatantly obvious that faith is not by works!). In fact, Romans 10:17 directly contradicts this interpretation: "Consequently, faith comes from hearing the message, and the message is heard through the word of Christ." But what about the gift of faith mentioned in 1 Corinthians 12:9? God may give a particular person the spiritual gift of faith, enabling them to trust God to bring about certain things for which they cannot claim any divine promise recorded in scripture. The spiritual gift of faith is something very different to the faith referred to in Ephesians 2. Therefore, it is best to understand the gift of God as "salvation through faith, on the basis of grace". Salvation is God's gift to us and our response should be to accept this gift by faith. This results in the translation: "For it is by grace you have been saved, through faith--and this salvation is not from yourselves, it is the gift of God - nor is this salvation by works, so that no one can boast."