I agree that Christ died for all (redemption), potentially saving all. However, not all (nor even perhaps a majority) will accept that redemption and be saved. While the terms are often used interchangeabley, "redemption" and "salvation" are distinct terms with different meanings.
Redemption: Our Lord "gave himself as a ransom for all." There is a universality for what Christ accomplished on the Cross. This is what "redemption" means. And because Christ was resurrected, all will be resurrected. Death will die. But there are two resurrections indicated in the scriptures, one for the saved and one for the damned , see summary at
What is the first resurrection? What is the second resurrection?).
Salvation, however, requires accepting that redemption. None who reject it can be saved. There is coming a time (the Day of Lord) when God, in essence, says “Time’s up!” He is not going to allow sin to forever exist, not in His Creation and certainly not in His Kingdom. But some people are children of the devil and not children of God, they are not lost sheep, they are goats. And you cannot turn a goat into a sheep, even if they bleat similarly.
- “Children of the Devil” -- Goats and wolves in sheep’s clothing as opposed to God’s sheep (both lost and found) – these references are to people, not just nations.
- Jesus: John 8:42-44, Matthew 13:37-42, John 6:70
- John: 1 John 3:10
- Paul: Acts 13:10
To summarize: All are redeemed by the sacrifice of Christ and by His resurrection and all will be resurrected. However, salvation into the Kingdom of God requires fully accepting this redemption (admitting they are sinners in need of it). None who reject this redemption (refusing to repent and trust in Christ) can be truly saved into the heavenly Kingdom of God.