1 Corinthians 3:10-15 is an analogy of salvation and the Christian life. True Christianity and salvation is built on one foundation; Christ. And we build on that foundation with gold, silver, precious stones, wood, hay, straw, each being tested by fire when Christ returns. If it survives the fire, you will receive a reward.if it burns up, you will suffer loss, though you will be saved.
So I really just re-wrote the analogy, I didn't clarify it. So here goes. After we are saved by the faith in Christ's saving grace, we have a duty to live as saved people, changed by the understanding of grace. We are not saved by our changed lives, but we are responsible for living differently. Sin is going to still be our lives, but it shouldn't BE our lives. We build on our salvation with different levels of Christian living. Some things we do are great and further the kingdom of God. And some things are not good at all, and we add to the confusion about salvation. These things we do, after becoming a Christian, will be tested at the day of judgement. If they are good things the will be stand the test. If they are not, they will fail. Gold, silver, and precious stones will not burn. Wood, hay, and straw will.
This passage ends with Paul restating that these works don't earn someone salvation. Salvation comes from Jesus Christ and Him crucified. Once we believe this, we are saved. Our lives from that point on need to be lived as though we understand the grace we've been given. Ephesians 2:8-9,"For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast."