Being "saved" (Salvation), is necessary because of sin. For a full in depth discussion of sin please visit Ariel Ministries.
Dr. Arnold G. Fruchtenbaum defines sin as "anything contrary to the character of God." The character of God is perfect. So anything which is not perfect is sin, or sinful.
This includes doing that which we ought not do, and not doing what we ought to. It also includes not believing in God's anointed one (John 3:18), the Messiah (Christ). Sin also has a sense of missing the mark, not quite hitting the right target.
God's standard is "be holy, even as I am holy". He accepts nothing short of perfection. He cannot, it is His nature. So we have a catch 22. We are not perfect but we must be if we want to avoid the smoking section in the life to come.
This situation is similar to an Olympic swimmer dropped overboard in the Atlantic without a life jacket. He may be the best swimmer in the world. He will die however, drown, unless he is rescued. We are drowning in a sea of our sinfulness. There is nothing we can do to fix this problem.
The Bible says:
Rom 3:23: for all have sinned, and fall short of the glory of God;
1Jn 1:8: If we say that we have no sin, we deceive ourselves, and the truth is not in us.
Therefore, everyone, however good a life he has led has missed he mark, and needs to be saved.
