Jesus only answered the question "How can I be saved?" on a few occasions. So obviously these few answers are very important.
To the rich young ruler he said, "Sell all you have and give to the poor, and follow me." (Luke 18:18, Luke 18:22)
To a lawyer he said, "Love God and your neighbour." (Matthew 22:35-40)
To the multitudes he said, "If you don't forsake all you own, you can't be my disciple." (Luke 14:25, Luke 14:33)
We insist that faith in Jesus be proven by obedience to these commands, which simply is not happening in traditional churches, with their "Lord Lord" statements of faith and nothing more. (James 2:14-20; Luke 6:46)
The devil himself has no argument with the virgin birth, the Trinity, the resurrection, divinity of Christ, etc. But he, along with the churches, would pay dearly for a gospel to substitute the one preached by Jesus.