I used to understand this passage something like this: "God looks after His people and nothing will go wrong for us." Now that is a rather simplistic understanding of this passage and it is one that does not help us much when we fail or when disease comes or when someone hurts us.
If we read this verse in its broader context: Romans 8:27-29 (New Living Translation), it reads.
And the Father who knows all hearts knows what the Spirit is saying, for the Spirit pleads for us believers in harmony with God’s own will. And we know that God causes everything to work together for the good of those who love God and are called according to his purpose for them. For God knew his people in advance, and he chose them to become like his Son, so that his Son would be the firstborn among many brothers and sisters.God has been teaching me a few things through this passage and through circumstances in my life. If we look at the passage in the broader context we realize a different emphasis. The emphasis is not on how everything is going to work out well for me. Or to put it more simply, it is not all about me.
Verse 27 makes it clear that one emphasis of this section is God's will - what He wants for the world. Verse 29 makes it clear that another emphasis is making us become more like Jesus. If I look more deeply at this I realize I need to have a different understanding of this passage. I realize that it is even more helpful than I thought in seasons of failure or success.
God is in the business of making me the kind of person He wants me to be. He is working on making me more like His Son, Jesus. In good times and bad times, the goal is the same. God wants me to daily become a bit more like Jesus. And He wants me to become more like Jesus so that together we can accomplish His will here on earth.
So God is teaching me that whether I succeed or fail, my comfort is not the primary goal. I need to look beyond myself to what God chooses to accomplish through my life. How might God's will be accomplished through the things that are happening to me? How are these circumstances making me more like Jesus so that I might serve others better? With this broader perspective, I can truly say, "God causes everything to work together for the good of those who love God and are called according to His purpose."