Thank you, menageriekeeper. I would like to add a little more to Amy:
Atonement is NOT forgiveness. If it were, then Christians would not have to confess their sins to the Father and find He is faithful and just to forgive! It would already be an accomplished fact, but it is not.
Here is some from 1 John:
My dear children, I write this to you so that you will not sin. But if anybody does sin, we have one who speaks to the Father in our defense -- Jesus Christ, the Righteous One. He is the atoning sacrifice for our sins, and not only for ours but also for the sins of the whole world.
1 John 2:1-2
Now back up to the verses before this:
If we claim to be without sin, we deceive ourselves and the truth is not in us. If we confess our sins, he is faithful and just and will forgive us our sins and purify us from all unrighteousness.
1 John 1:8-9
So you see, atonement is finished, an accomplished fact. But it is not forgiveness. That for each of us who are His is an ongoing thing and connected to our confession and repentance. Because, when we were born again in the Spirit, we were given hearts that do not want to sin in place of our old hearts which always tended toward sin, confession and repentance become easier and easier with time. But they are always necessary as long as we live in these earthly bodies and sin.
I hope that helps a little on that one.
Jesus said that a man dies in his sins if the man does not admit to Jesus being God Himself. So that part is entirely dependent upon the man. Jesus simply made is possible for every man to be saved by His atoning sacrifice which, again, satisfied God's justice. But forgiveness is a matter of God's mercy -- again something different.
Then you asked if general revelation is salvation. Menageriekeeper answered you on that one. The short answer is 'no'. The longer answer is from Paul in Romans 1-7. The medium answer is that it depends on what a man does with general revelation -- is he going to go for the truth or does he prefer the lie?
The reason I gave you this link --
http://www.ldolphin.org/zodiac/index.html -- is because it answers your question about people from all time and places knowing something about the Promise of the Redeemer to come. Four of us contributed to this article (I was Helen Fryman before I married Barry Setterfield). I was quite skeptical about this subject myself until I started studying it and seeing the actual evidence/data. David himself said the message was in the heavens -- there for every language and nation. Was he wrong?