The book of Acts recounts the spread of the early church and the manner in which Christ works to take the gospel from Jerusalem, to Samaria, and finally to the end of the earth (Acts 1:8). Your sermon from Acts 7:1 – 8:1 must focus on Stephen’s speech and death. You must help God’s people to understand the general thrust of his sermon before the Sanhedrin and why Stephen was able to face death with such confidence. In terms of application, once again you could focus on the need for day-to-day obedience and that this is the manner in which the Spirit will strengthen us for obedience in times of difficulty.