A lesson without pain is meaningless. For you cannot gain something without sacrificing something in return.

All right people, listen up! If you've got a family back home waiting for you or if you just want to save your own skin, turn around and walk away. Also, women! I have no intention of fighting any women!

There's no such thing as a painless lesson. They just don't exist. Sacrifices are necessary. You can't gain anything without losing something first although if you can endure that pain and walk away from it, you'll find that you now have a heart strong enough to overcome any obstacle. Yeah, a heart made fullmetal.

What?! I'm not small! It's the world that's too big!!

You cant gain something, without giving something in return

Told you, Rose. Get too close to the sun, and you'll burn." -Edward Elric

Greed (as Ling): You humans always get all "holier-than-thou" when it comes to this stuff... I really don't get you. Edward: It's called having integrity. You should try it sometime