Live and act by the words one express. ‘Walk’ is used to mean one’s actions, so to walk the talk is to act upon one’s convictions, not just say them but apply them.

“I’ve listened to him explain why he can handle this job, but I will wait and see if he can walk the talk.”

“My Christian friends often quote Jesus, but instead of listening to them, I watch to see if they walk the talk or just talk instead.”