We are talking about YOU and ME! If WE don't give mercy WE will not receive mercy. It's about YOU and ME. If WE kill others WE will not receive mercy from God!!!!!!!!
Since you put it that way, ok. If I execute someone for murder, I would definitely expect to get executed if I murdered someone. If I murdered someone, you know what? I would expect the death penalty to be used. Even if I didn't execute anyone, I would still expect it! I think almost everyone, deep inside, knows that if they murder, they should pay with their life!