In Romans 5 Paul states something a bit obvious – Jesus life is more powerful than Adam’s sin in its effects.
12 When Adam sinned, sin entered the world. Adam’s sin brought death, so death spread to everyone, for everyone sinned. Yes, people sinned even before the law was given. But it was not counted as sin because there was not yet any law to break. 14 Still, everyone died—from the time of Adam to the time of Moses—even those who did not disobey an explicit commandment of God, as Adam did.
Bad news, it only took one man’s sin for death to enter the world and for everyone to die. We see that around us all the time. The inevitability of death stares every man in the face no matter how good they are.
17 For the sin of this one man, Adam, caused death to rule over many. But even greater is God’s wonderful grace and his gift of righteousness, for all who receive it will live in triumph over sin and death through this one man, Jesus Christ.
18 Yes, Adam’s one sin brings condemnation for everyone, but Christ’s one act of righteousness brings a right relationship with God and new life for everyone.19 Because one person disobeyed God, many became sinners. But because one other person obeyed God, many will be made righteous.
I find it difficult to understand how the free gift of new life for everyone can be greater than Adam’s sin if, in fact, it doesn’t apply to everyone. What I mean is, death applies to everyone so therefore life must also apply to everyone for it to be greater. That seems obvious enough.
So I would argue from this and from Scriptures concerning the Book of Life, that the default position of every man is that they are written in the Lamb’s Book of Life because of Jesus’ death on the Cross. You have to have your name erased from the Book of Life to lose that life. Only Overcomers are guaranteed that that won’t happen to them (see Exodus 32:32 and Rev. 3:5).
However if you want to appropriate and see the effects of that life in this world then you need to receive it now. Actually, if you are reading this don’t take the risk and presume you are there. Make sure you are experiencing the reality of the love of Christ in your life now. The only people who can really be assured they are in the Book of Life now are those who can hear God the Father’s whisper in their heart to which they respond: “Abba, Father”. No amount of thinking it can give that assurance.
But let God be gracious in your heart, He is not willing that any should perish. Who knows, perhaps the exclusive evangelical doctrine which says that every man must believe the way we do to be saved is not quite right after all?
Let us not think that everyone around us is going to hell just because they don’t go to our church. God knows their hearts, very often we don’t.