This passage is found in the Revised Common Lectionary Year B (Most recently Oct 18, 2015)
Summary: Don't get too lost in the Greek in this week's passage. The point is that two key disciples are asking really silly questions. It proves Jesus an opportunity to say to them directly what he has been suggesting to them all along: While they do not need to be crucified, to be a follow of Jesus means following him to the cross, to the suffering of the world, to the surrender of our will and to the death of sinner. I focus a fair amount on the word "ransom," hopefully opening a different way of thinking about this.
ποτηριον ("poterion" (pottery!), meaning "cup", 10:38) There are three cups in Mark's Gospel! Can you name them? The first is in the story of a glass of cold water. The second is here. The third is the communion cup. The cup of following Christ, while it may be lived out in small ways, is no small thing, but the giving of our life to Christ. Or better stated in Gospel form (from Luther): All this he did that I may be his own.
βαπτίζομαι vs βαπτισθηαι ("baptize", 10:38) I want to point out a distinction in verb tenses here. When Jesus refers to the baptism of the disciples, he uses the aorist tense, suggesting a one-time event. When Jesus refers to his own baptism, he uses the present tense, suggesting an on-going event. Jesus says, "which I am being baptized right now"is in the midst of his baptism as he begins his long road to the cross. Which makes us wonder that if we are to experience the baptism of Jesus as our own, must not our Baptism also be an on-going process?
κατακυριευουσιν ("literally over-lord", 10:42) Just a little note for preachers personally rather than for a sermon. This verb shows up rarely in the New Testament, but it does show up in 1 Peter 5:3, as an admonishment to pastors not to Lord over their power!
δουλος ("servant" or "slave", 10:44) This word appears repeatedly in the New Testament as a model for Christian life and service. As the Thayer Greek Lexicon reminds us, δουλος του χριστου (servants of Christ) are those whose service is used by Christ in extending and advancing his cause among [others]: used of apostles, Rom. 1:1; Gal. 1:10; Phil. 1:1; 2 Tim. 2:24; Titus 1:1; James 1:1; 2 Pet. 1:1; of other preachers and teachers of the gospel, Col. 4:12; 2 Tim. 2:24; Jude 1:1; of the true worshipers of Christ
Do we challenge our people enough to adopt a posture of servant-hood?
λυτρον ("redemption", 10:45). This word is a loaded term. It is often suggested that Jesus was the ransom whose death serves as the payment rendered for our sins, thus freeing us from this deserved punishment. Both Exodus 21:30, 30:12 convey this sense of λυτρον. I am not going to argue here against substitutionary atonement.
However, the Old Testament also puts forward another sense of λυτρον that I think works just as well, if not better, in this case. In Numbers 3, there is the (for most of us) relatively unknown story of the consecration of the Levites to the priesthood and how they are offered as a redemption (λυτρον). A surprisingly helpful commentary summarized the logic:
"...when God slew the first born of man and beast among the Egyptians, he consecrated the first-born of Israel to himself as a memorial of the deliverance. First-born animals were to be sacrificed to the Lord, but first-born sons were to be redeemed by the substitution of a payment of money. Now the Levites are taken by the Lord as the redemption of all the first-born males in Israel, and their very office becomes a perpetual sign of Israel's deliverance. The ministry of the Levites proclaimed to Israel the fact that all belong to the Lord, because he has delivered them. (75, Mays; 1963 Layman's Bible Commentary.")
In short, in the consecration of the Levites, God turns the sacrificial system on its head. God does not want sacrifices of first-born humans (and never did), rather, God wants the Levites to take the place of the first-born, not for death, but for service to God.
I am still fleshing this out, but I think you can make the argument that "ransom" can be utilized in a way where Jesus frees us to serve God without needing God to be angry with Jesus.
Perhaps it is something like this: Jesus is put forward as a ransom, but not simply for death, but for service to God. What God wants is not the death of Jesus, but the life, the service (which in his case, will include death). As we are baptized into Jesus' death and drink his cup, we too are put forward, not as a substitute punishment, but as something precious to God, namely, servants of God, becoming the new priesthood, in fact, a very proclamation that the Lord has delivered us.
Confession: I want to flesh this out, but I think the Levite consecration is a very different way of thinking about this.