The Law of Equivalent Exchange

"Fair" is what The Gate will perceive
When alchemy is done
If you give, you shall receive
It's no child's game for fun

Transmute enough substance
You'll gain something new
When you pass enough judgments
You'll gain something true

But transmuting life
Is extremely forbidden
It's a double-edged knife
And a rule that's been written

Edward learned that truth
When Truth tried to derange
He is the living proof
Of Equivalent Exchange