Paul was writing about Jesus, the only foundation of the church, at a time when false teachers were saying that either supernatural signs or human logic should be at the centre of the church (1 Corinthians 1:22).  Even some who accepted the ultimate authority of Jesus still wanted to shape the church in a different way than Jesus had instructed His apostles.  

Paul used the analogy of two different building materials: those which would come through a hot furnace unchanged, and those which would be destroyed.  Gold and silver could only be made better (purged of impurities), and precious stones would be unaffected.  However wood, hay and straw would never be seen again; burnt to ash.  When Jesus comes back, that will be the Day when He will test everything that we have done against His own perfect standards (Malachi 3:2-3).

When we see Jesus, He will reward every spiritual builder whose building has godly integrity after His fiery testing (Matthew 25:23). The people who start with the foundation of Jesus but build with rubbish will still be saved, but they will lose their reward – like a person escaping from a burning house and leaving everything behind to be swallowed up by the fire: and the Master will not be able to commend them.

Every believer is a builder.  They build the shape of their own lives, and partly shape their families' lives, their friends' and the church.  Yet churches can forget why they are there.  We are not to create our own empires or exploit our own ideas and talents, but to build God's kingdom.  Paul was speaking to everybody in the church but also to the leaders, and the people who chose them.  His message was direct: firstly, the church is all about Jesus  - His death, resurrection, ascension and coming again must be the centre.  Secondly the church must be built on what God has said and not what human beings like to think that He is saying.  Thirdly, the test of a person or church is not what we like doing, but what Jesus knows will last for eternity.  He will remove all rubbish on the Last Day and reward everybody who has built their lives and others the way He has commanded.  So let us watch ourselves and those whose lives we affect so that Jesus will be pleased to reward us when He comes again (1 Timothy 4:16).