Believing in Jesus Christ and in the One who sent him for our salvation is necessary for obtaining that salvation. "Since 'without faith it is impossible to please [God]' and to attain to the fellowship of his sons, therefore without faith no one has ever attained justification, nor will anyone obtain eternal life 'But he who endures to the end.'"
As for St. Augustine's opinion on the matter, he couldn't be clearer: "If, however, Christ did not die in vain, then human nature cannot by any means be justified and redeemed from God's most righteous wrath--in a word, from punishment--except by faith and the sacrament of the blood of Christ." (On Nature and Grace, 2).
That's old hat. The new hat is something completely different. What does Scripture say? "I Am the God that changes from day to day. I Am whatever you say I am. Y'all come back soon y'hear, else ya be not indulgin' on Friday like ya could be (until they change my mind for me)."
People that ate meat on Friday went to hell. Not anymore. That's because the Church has the keys to heaven and hell. They can lock and unlock at a whim's notice. All that has to happen for it to go into effect is publishing it (and not in some classified somewhere buried on 26E), but you know, ex-cathedra and its The Law.
I used to try to keep up with all that, but it proved too much, so I got me an Electric Monk to believe stuff for me. One day I checked the logs, you wouldn't believe what this guy was believing. Sheesh. Then the batteries went dead. So I got me a Bible and read it. Seemed pretty clear, cut, and dried to me. I threw the Electric Monk into the trash.
I heard they came out with a new modeld though. Its supposed to have some really super believing power.