a part of a Christian church ceremony in which a priest gives a talk on a religious or moral subject, often based on something written in the Bible

The Reverend William Cronshaw delivered/preached the sermon. 威廉‧克朗肖牧师进行了布道。

Today's sermon was on the importance of compassion. 今天的布道是关于同情心的重要性。

a long talk in which someone advises other people how they should behave in order to be better people

I really don't think it's a politician's job to go delivering sermons on public morality. 我确实觉得对公共道德作长篇说教并不是政客的职责。