I have never built a house from foundation to roof. Some of you may have, though I would not be surprised. I built a few roofs in college on mission trips with far wiser men than me guiding the way.
If you build a house or a roof or anything else and it is not square, it won't last long. A square framing is sturdy and stable against the elements. Jesus tells the parable of the man who built his house upon the sand and how it blew away, but the man who built his hand upon the rock, his house remained.
We must have a firm foundation on the rock of the truth of God. Yet we also must be made right. It doesn't matter if we stand on a strong foundation and yet are not square.
This is what justification means. Dikaosune in Greek means to be made right, to square something up. In Latin, the word is iustitia, where our word justify comes from. Justice and righteousness are two translations of the same word in Greek or in Latin. Article IX says that we are made right only thanks to the grace of Jesus Christ. We don't earn it. If we do more good things than bad, that does not make us right and square. The Good news of Jesus Christ is that we are saved by grace through faith, as Paul says.
As well, as Article IX says, this is a comfort. We should be comforted by God's grace toward us.
Justification does not mean that we can do whatever we want. This is called antinomianism (which means against the law). Grace doesn't mean you get to do whatever you want but that God, in fact, heals us so that we can truly want what we need to live and no longer want what destroys us.
You are saved by grace through faith, but that is not the end of the story. Paul begins Romans 5 by saying, "Now that you have been saved by faith..." He still has a lot more to tell the people of Rome. In being justified we are made right on the foundation of Christ for life with God now. Not only a future promise, but the present reality of the kingdom of God here.
Article IX Of Justification
We are accounted righteous before God only for the merit of our Lord and Saviour Jesus Christ, by faith, and not for our own works or deservings. Wherefore, that we are justified by faith, only, is a most wholesome doctrine, and very full of comfort.