There remains a precious jewel in every person, which is stronger than any outward pressure in their lives. It remains inviolable, even in those who feel that they are lost in their rottenness. No matter how badly they have ruined their lives, this jewel remains in them; it is as certain as that God was reconciling the world to himself in Jesus Christ. There is something in each person that will never be lost, something that can always be resurrected. That is the gospel.
Source: Everyone Belongs to God