Spe Salvi Encyclical Letter - Part 46. Pope Benedict XVI
He does this using images which in some way try to express the invisible, without it being possible for us to conceptualize these images—simply because we can neither see into the world beyond death nor do we have any experience of it. Paul begins by saying that Christian life is built upon a common foundation: Jesus Christ. This foundation endures. If we have stood firm on this foundation and built our life upon it, we know that it cannot be taken away from us even in death.
Then Paul continues: “Now if any one builds on the foundation with gold, silver, precious stones, wood, hay, straw—each man's work will become manifest; for the Day will disclose it, because it will be revealed with fire, and the fire will test what sort of work each one has done. If the work which any man has built on the foundation survives, he will receive a reward. If any man's work is burned up, he will suffer loss, though he himself will be saved, but only as through fire” (1 Cor 3:12-15). In this text, it is in any case evident that our salvation can take different forms, that some of what is built may be burned down, that in order to be saved we personally have to pass through “fire” so as to become fully open to receiving God and able to take our place at the table of the eternal marriage-feast.