Imagine a boy who broke his mom's vase and didn't tell anyone. He's in the living room watching TV and hears his mom's footsteps in the hallway. What does he do? His heart starts racing and he wants to hide or run! Even if his mom was only coming to give him a kiss, he runs because his "conscience" is accusing him. He turns into a scared little kitten.
But what about the boy who cleaned his room and did everything right? When he hears his mom's footsteps, he runs to hug her! He isn't afraid. He's as strong as a lion. The Bible teaches that doing the right thing (telling the truth, obeying) is what gives us courage.