Exodus 3:1-8a, 13-15

This passage relates an extraordinarily important moment in the life of Moses and in the covenant relationship between the Lord and the people. There are a number of key details that require attention. The first is that the call of Moses occurs by divine initiative rather than any special capacity or plan of Moses. While the reader knows that Moses' life has already been touched and guided by the Lord, we see that Moses does not fully comprehend God's purposes - he has settled down in the life of exile with no expectation of any significant change in his status. It is the Lord Who reaches out and calls to Moses. Even then, Moses must be instructed how to behave in the moment. the glory of God is such that Moses must be cautioned to approach with respect. 
Next, we must attend to the identity of this mysterious God Who calls to Moses. It the same God who called to Abram - "the God of Abraham, the God of Jacob, and the God of Issac." This links this new development to the earlier events in Genesis. There God took the initiative and entered into a special covenantal relationship with Abraham and his family. God also made promises of progeny and land that are now under assault by Pharaoh who would hold the people from their Promised Land and contradict divine will by attempting to reduce the numbers of Hebrews. Now we see the fidelity and the power of this God Who has drawn near to the family of Abraham. Even as the story appears to have grown darker, that God has remained with the people and stands ready to deliver them. In this new moment, they will be more than a family, they will go forth from Egypt a nation and they will live by this defining relationship with the Lord. 
Moses treats God and the call of God with proper respect - "here I am" - but he seems surprised and even intimidated by the call of the Lord - "who am I," he asks. 
God then shares the Divine Name, "I am Who I am." Here is another surprise. In ancient Jewish culture, names mattered. To know someone's name gave a person the power to bless and to curse. Only those in a trustworthy relationship would reveal their personal name. This action by God bespeaks the special nature of the covenant. God behaves as one of the family. The name itself remains mysterious and difficult to translate. It is some form of the verb "to be" and many suggest that it is related to the language of creation. Perhaps we may also wish to note that Moses has said "here I am" and "who am I," and now God responds with a name that plays on this language and asserts an identity at the very heart of creation and of being itself.

Psalm 103:1-2, 3-4, 6-7, 8, 11

First Corinthians 10:1-6, 10-12

This is a personal song of thanksgiving. Its original composition may have expressed gratitude on the part of a sick person who has been restored to life. The poetry of the Psalm draws connections between physical healing, forgiveness of sins, and the great acts of deliverance that the Lord has done for Israel in the past. At the confluence of these connections, we see the nature of this merciful and forgiving God Who works for the good of His people. 

Paul faced many challenges in the behavior of his Corinthian community. A number of those challenges apple to revolve around their presumption of their superiority. Remember that they value their fine rhetoric and make even their spiritual gifts cause for comparison and division.
In this passage, Paul calls them to recognize the danger of their presumptive self-satisfaction. He employs tradition Jewish Midrash in his teaching. With Exodus imagery providing the model, Paul is teaching them about the nature of baptism and reminding them of the need to continue responding faithfully to the covenant relationship. Those who were delivered from slavery in Egypt, passing through the waters, knew the providential care of God and still faced the temptation to fall away and find themselves lost. Likewise the Corinthians - even though they have been delivered from death by the waters of baptism and now know that same providential care, they must learn from the example of the past and be certain to remain focused on their relationship with the Lord. 

Luke 13:1-9

When compared with the Gospel of Mark, the Gospel of Luke appears to have less of a sense of urgency. In fact, Mark is noted for its clear message of eschatological urgency. It challenges the reader to understand that the time is short and a response of repentance and belief is required immediately (this word appears more than 40 times in Mark).
Luke, by contrast, gives more information about Jesus' teachings for the longterm. Luke seems to presume that the return of the Lord may not be quite so immediate and that believers must be about the work of living Christian discipleship as they await the consummation of God's kingdom. Thus this Gospel includes advice for forgiveness and for the proper place and use of material goods.
Having acknowledged this, we need to remember that Luke has not forgotten that this world is passing away. If the urgency of response is longer term, it has not ceased to be urgent. 
This passage from chapter 10 is unique to Luke and it addresses the danger of complacency. In the passage, Jesus offers teaching that touch on the nature of God and the quality of human response. First, the Lord makes it clear that the mercy of God is not undone by the random nature of disasters. His disciples should not indulge the perennial temptation to reduce God to the vindictive level of human beings. Likewise, they must not try to make life more predictable by suggesting that every disaster is the result of some mistake or offense - they implied message being that the righteous are safe. 
The Lord reminds his disciples that life is indeed unpredictable, uncertain, and all too brief. In the face of the passing nature of human existence, all that matters is faith in the God of mercy and a humble repentant response. The passage also emphasizes that this is a God Who permits second chances, but even this should not fool us - time remains short and the urgency of the need for response is high. The Lord will return at the end of time. Even if that moment has not come, each of us inevitably faces our own personal apocalypse. The time to prepare for that end is now.