What does fire symbolise in Christianity?

In many verses of Scripture, we see fire pictured as works' of God's Holy Spirit (Acts 2:3). God's Spirit then uses fire to announce or reflect God's presence as it did with Moses and the Israelites following the column of fire in the desert, or when God descended upon the Mountain in fire and lightning/thunder to seal the covenant agreement. It also expresses His passion within the new Christian (see Acts 4:31) , and it is seen as God's way of purifying His New Creation (see 2 Peter 3:10 for entire universe and other examples like Isaiah 6:6-7).