I don't know about you, but I have found that question in John 5:6: "Do you want to be well?" a very challenging one. Clearly it is a question addressed to the will of this man. The Greek word emphasizes: Do you will to be well? But it's not just about his will-power is it? Is Jesus is asking about how much his will-power is willing to trust in Jesus' power for healing?
And there are several dimensions to the healing too. Obviously it's about physical healing because he is a long-term invalid. But there is also moral healing and even social healing hinted at in this story.
As I prepare the sermon I see its main impact as:
By God's grace what this sermon will SAY : Jesus gives a reality check about our will-power's willingness to trust him for healing - physically, morally and socially. What the sermon will DO: confront our will-power and commitment to trust in his power to make us more whole.
Lots of issues come into my mind and heart from this story. Let's keep open to what He wants to teach us. What particularly impacts you?