But because of your hard and impenitent heart you are storing up wrath for yourself on the day of wrath when God's righteous judgment will be revealed. (ESV)
I was never very good at science. I believe my worst subject in school was chemistry. One of the things I do know is that if you do not properly recognize what different chemicals and chemical combinations will produce you could be in a whole lot of trouble. If I were a scientist I am fairly certain I would blow myself up.
One of the subjects that mankind seems to fail at is the study of God. We tend to think of him as an old grandfather type in the sky. We do not recognize him as a holy and righteous judge. We also err in our evaluation of ourselves, particularly our sin. We think that our sin is not a big deal. We argue in our minds that we aren't really that bad. We certainly aren't as bad as our neighbor.
To mix the fury of a righteous God with the built up pressure of a lifetime of unrepentant sin is a chemical equation that is guaranteed to provide a devastating explosion. I'm not a good scientist, but I know enough to heed the warning of Scripture. What God promises he will surely do. God warns us that living a life of sin that we refuse to repent of will lead to his terrible wrath.
It is interesting to note that our sin is described in terms of accumulating and building up for an ultimate destructive end. In other words, it is like pressure building. Think of it like boiling water. The more heat is applied to the water, the more bubbles appear. It starts as just a few small bubbles, but eventually it is a rolling boil as heat continues.
What is the solution? (pun intended) Repent! God will forgive you of your sin. The wrath that he would pour out on you is applied to the cross of Christ as you place your faith in him.