For the study itself, I take one section of the book, read through it prayerfully, and try to find a way to make it real in my life. It's an old Protestant trick that many Catholics would do well to learn, although my time in the Catholic study group Familia really helped me to develop this skill too.
Currently I'm going through the Old Testament book of the prophet Joel, and I wanted to share one passage that has really resonated with me. The story up to this point is that God's people had rejected him, so he sent an enemy army to go and lay waste to their land, to loot the temple, and to put the people into slavery. After the Israelites had had enough, they cried out to the Lord in repentance and he came to their rescue. If you study the history in the Old Testament, you'll see that this is a fairly common pattern. Nothing new here.
Hold on, I'm getting to the good part.
After saving his people, the Lord then turns his hand against the enemy army he sent to conquer his people. When the army wonders why they're now suddenly the target of God's wrath, he responds: (Joel 4:4-8, which might show up as Joel 3:4-8 in some versions):
Now what have you against me, Tyre and Sidon and all you regions of Philistia? Are you repaying me for something I have done? If you are paying me back, I will swiftly and speedily return on your own heads what you have done. For you took my silver and my gold and carried off my finest treasures to your temples. You sold the people of Judah and Jerusalem to the Greeks, that you might send them far from their homeland. See, I am going to rouse them out of the places to which you sold them, and I will return on your own heads what you have done. I will sell your sons and daughters to the people of Judah, and they will sell them to the Sabeans, a nation far away.
Pretty harsh, eh? This is one of those "eye for an eye" texts that are so difficult to reconcile with the idea of a loving God. Perhaps this passage can't be understood so literally though.
Taken as hyperbole, the core point would seem to be that God still treasures his people and is fiercely devoted to protecting them. The intended audience here is the Jews, after all, not the gentiles from Tyre and Sidon. God is sending his people a message here: God's forgiveness is a complete forgiveness. He doesn't hold a grudge after the reconciliation, wagging his finger & saying, "You did have it coming, you know."
God is so eager to wipe all traces of his people's iniquity from his mind that he is filled with a baffled rage against the nations that would dare attack his beloved. It's almost like he forgets that he was the one who pronounced that very doom upon his people, and he was the one who commissioned the enemy army to invade. Psalm 103:12 says, "As far as the east is from the west, so far has he removed our transgressions from us." That's what we see happening here. God has forgiven his people so completely that he doesn't associate the destruction they had gone through with their past sins. All he sees is that somebody hurt his beloved people.
I'm also reminded of a line from The Hiding Place, by Dutch author Corrie ten Boom, whose family hid Jews from the Nazis during the Second World War (amazing book, by the way). Leading up to the war, her wise & aged father witnessed some of the atrocities the Nazis were perpetrating and sadly shook his head, saying he felt sorry for the Germans. Baffled, Corrie asking him why he should feel sorry for people who led such brutality. His response: "They have touched the apple of God's eye."
Through the new covenant, I am now one of God's chosen people. I am the apple of his eye! When I turn to him in true sorrow for my sins, his forgiveness is a done deal. The true power of repentance comes from the fact that God always responds to us with perfect forgiveness; when we reach out to him, we find that he is there, having extended his arms to us long before we noticed. The challenge I derived from my meditation on this section of Joel was to bear this fact in mind the next time I felt hesitant to approach the sacrament of reconciliation. I extend that same challenge to you, gentle reader.