The first rule of being a ninja is: Do no harm. Unless you mean to do harm. Then do lots of harm!
I do not wish to fight. But cast a stone into the lake, and the ripples will return to you.
You are extraordinary, my sons. Unlike anything the world has ever seen. Bowed in greatness, destined to protect the people of New York! A dark force is growing: a criminal organization known as the Foot Clan, so named because they step over the good people of this city with no regard. Their leader, Shredder, will come at you with ferocity. His Foot Clan will outnumber you! The people of New York will look upon you as their only hope. Eyes focused! Elbows locked! Stance lowered! Be one with the blades! I know you are eager to answer their calls. But your training is not yet complete. The world below must remain your home. As your father, you must trust me and be patient. You are not yet ready to go above ground, but I believe when that day comes, when you rise to the streets, you will be responsible for amazing things.
Teenage Mutant Ninja Turtles - 2014