Dear Dave,
You are talking about 'Obedience to God' and using the word 'Faith' to describe it. Yes, that is how the word was often used, and that is why the Antichrist hijacked the word.
Under the Antichrist, the idea became current that if one could sufficiently convince oneself intellectually that a certain set of Doctrines could have a certain Magical Effect, then they would. It is commonly expressed in formulas similar to "If you have Faith in Jesus, you will be Saved". You can't compare this to Moses or Noah. God presented Himself to Moses and to Noah, prior to any demands for explicit obedience. There was never any question afterward as to whether or not they would have a powerful intellectual conviction in the Existence of God.
Also, it is not necessary for my argument to suppose that Satanic Influence was absent from the Old Testament. It most certainly was not. From the very Beginning Satan has challenged every Move God has ever made. Afterall, it was not three Generations after Abraham when Satan took over the Jews with the Usurper Jacob.
We also have to look at the Human Interests involved in the notion of Faith. For instance, even if it was True that Murdering the Messiah could procure Salvation for Mankind, why should we suppose that Faith should be required? If Forgiveness were to be Unversal and otherwise Unconditional, then is God not being a bit petty by requiring Knowledge and Acknowledgment. You would think that if God were going to give out a Dispensation that totally emempts Humanity from Morality, that He would be no great stickler about trivial requirements. Afterall, Humanity was not required to have Faith in the Curse of Adam, or to have Faith in Original Sin, or Faith in Death, or Faith in Taxes, or Faith in the nutrition of Food or Faith Orgasms. So why should the only thing that requires Faith be Salvation? I will tell you why. Paul needed a Product to sell for Money. That product was Faith.
