To interrogate is to ask questions. Use interrogation pronouns - who, what, why, or when - to help locate a key word for the sermon.
Example
Passage: Romans 5:1-14
Subject: Suffering
Theme: Joy in suffering
Proposition: Every believer should rejoice in suffering.
Objective Sentence: Therefore every believer should rejoice in suffering.
Interrogation Sentence: Why should every believer rejoice in suffering?
Interrogation
Preaching Tips
Who, What, Why, When