Nevertheless, all people who do what is good as a religious practice—not only Christians but also non-Christians—are accepted and adopted by the Lord after they die. The Lord says, “‘I was hungry and you gave me something to eat. I was thirsty and you gave me something to drink. I was a stranger and you took me in. I was naked and you clothed me. I was sick and you visited me. I was in prison and you came to me.’ And he said, ‘As much as you did this to one of the least of my people, you did it to me. Come, you who are blessed, and possess as your inheritance the kingdom prepared for you from the foundation of the world’” (Matthew 25:34–36, 40). . . .
It is important to realize that people who do what is good only because they possess a natural goodness and not because of their religion are not accepted [by the Lord] after they die. This is because the only goodness that was in their goodwill was earthly and not also spiritual; and spiritual goodness is what forges a partnership between the Lord and us, not earthly goodness without spiritual goodness. Earthly goodness is of the flesh alone, and is inherited at our birth from our parents. Spiritual goodness is goodness of the spirit and is born anew with the help of the Lord.
from Regeneration, Pages 37, 38