Not too hard.

Dad tells kid “never harm your neighbors even when threatened by a bully”.

Bully wants dad’s help harming a neighbor. Bully threatens dad. Dad can either stand strong and live the example he wishes his child to follow, or cave displaying the opposite of what he said.

In humans what you do is far more important than what you say. You can tell a kid to tell the truth a thousand times and if you show by example that lying is ok, they will lie.

Conversely if you live a life where you simply don’t lie for any reason, your kids will learn to live honestly.

Not sure how well this translates to LLMS. Probably not cleanly.