I almost forgot to do this! There are a lot of questions to cover, so I may miss some that caught my eye.
105. What is the Christian's proper response to theories of evolution regarding the beginning of the world?
The catechism's way of addressing the issue of evolution is pretty fideistic. It essentially says "The Bible speaks of a young Earth, so that must be true!" It also calls evolutionary theories "scientifically unverifiable."
This implies the LCMS holds to a Young Earth Creationism (YEC) understanding of the world - a literal seven days of creation, with the universe being around 6,000 years old. Although I once held to YEC I now consider myself an Old Earth Creationist (OEC). I accept scientific aging of the universe at about 13.7 billion years old, as well as a very old Earth and evolution. This is due to me mostly being an evidentialist - I go where the evidence takes me. Up until now I haven't seen very much evidence pointing to the viability of a young Earth. I see YEC/OEC as a doctrine of secondary importance, so I don't mention it often nor do I try to persuade others' stance on it.
107. Do people still have the image of God?
According to the catechism, we don't bear the image of God anymore because of sin. We are not the image-bearers that many people like to tell us. By accepting Jesus the image is rebuilt in us but won't be fully completed until after the end of this age.
108. How does the universe still depend on God? and 110. What does God do to take care of me?
One of the questions I've been wondering is, how active is God in my daily life? Or in general, just how much involvement does he have? Does he oversee and care for every single detail, or does he let us decide how the paths of our lives will go? The answers to 108 and 110 suggest that God sustains the physical world (by digging a bit into the grammar of the Greek it seems to be a passive thing) and he provides for and defends his followers. In his foreknowledge, God established the universe in a way that, through natural occurrences and human action, that his will would be done.
140. Has Christ redeemed only you?
A shock to my system: Christ has redeemed everyone, not just believers. This notion, called universal atonement, is a bit foreign to me. I suppose while everyone is redeemed, not everyone is saved because they lack faith.
213. For what do we pray in the Second Petition?
The Second Petition is the line "Your kingdom come" in the Lord's Prayer. I have long thought this was a petition for God to bring the end time sooner. Under Lutheran teaching, God's kingdom is already present. So in saying this we ask that the already present kingdom may be further edified.
215. What is the good and gracious will of God?
Christians today seem to obsess over knowing what God's will for their lives is. Who do they marry? What country should they be a missionary in? What should be their major in college? There are books and sermons on discerning God's will, even though he has shown himself generally tight-lipped in talking about it until we need to know.
The answer to this question is nicely summed in three phrases: obedience, evangelism, and proper instruction. How the specifics are worked out are left to God and man's free will.
218. How is God's will done in our lives?
Answer: when God defeats plans which oppose his, keeps us following godly behaviors, and supports us throughout our lives.
226. What does God want us to do for those who sin against us?
The answer to this is a real challenge for me to carry out. We are to forgive them and do good to them.
249. If Christ has already won forgiveness and salvation for us and gives us all this by grace alone, why do we still need baptism?
Apparently I'm not the first one who thought saying Jesus alone saves, but then adding baptism, seemed wonky. This is the closest the catechism came to answering the objection I had to Lutheran doctrine. Jesus alone saves, but it's distributed in baptism. I am not entirely sure this satisfies my objection.
269. What special authority has Christ given to His church on Earth?
This introduces a doctrine called the Office of the Keys. Honestly it's something I could devote an entire blog post to. In short, ministers can withhold divine forgiveness from unrepentant people, and it will be as effective as if God himself were denying them forgiveness. It is a bit weird but also understandable. Pastors work in the place of Christ and act on his authority.
292. Do all communicants receive the body and blood in the Sacrament, whether or not they believe?
I wonder how this applies not toward unbelievers, but those churches that don't believe the wine (or grape juice) and bread really are the body and blood of Jesus. It would appear that they still really are taking Jesus's body and blood, even though their official doctrine says it's just symbolic.