sermonize

To speak in the manner of a sermon; to preach; to propagate one's morality or opinions with speech.

And doe not our Prelates thus, when […] they disgrace and traduce Preaching, calling it in scorne, Sermonizing?

Don’t be alarmed, I am not going to sermonize—but what is almost as dull, to narrate.

To preach a sermon to (somebody); to give (somebody) instruction or admonishment on the basis of one's morality or opinions.

He wishes, I suppose, to sermonize me: but I shall not give him an opportunity—

“[…] we sermonised her on the presumption of attempting to teach such clever blades as we were, when she was herself so ignorant.”

To say in the manner of a sermon or lecture.

“Children, children! Woe, how you do sin!” Mrs. Kavarsky sermonized. “Come now, obey an older person […]”

1917, George Creel (uncredited author) and Douglas Fairbanks, Laugh and Live, New York: Britton, Chapter 17, p. 144, Then as one man they jumped to their feet and by reason of prolonged cheering gave national impulse to a thought which has since been sermonized from thousands of pulpits.

To inculcate rigid rules.

If you consider my letters in their true light as conveying to you the advice of a Friend, who sincerely wishes you happiness, and desires to promote your pleasures, you will both read and attend them; but, if you consider them in their opposite, and very false light, as the dictates of a morose and sermonizing Father, I am sure they will be not only unattended to, but unread.