Sermonize (verb)

To deliver a moralizing or preachy lecture or discourse.

Origin:

From the latin word sermo meaning talk, and -ize meaning to make or do.

Examples:

1. The preacher was known for sermonizing about the importance of living a virtuous life.
2. He was always sermonizing about the importance of hard work and perseverance.
3. She couldn't stand it when her parents sermonized about the dangers of drugs and alcohol.
4. The speaker spent more time sermonizing than giving useful information.
5. He sermonized about the importance of forgiveness but never practiced it himself.