And God will grow no talons at his heels, Nor antlers through the thickness of his curls. (11-12)
According to the speaker here, humanity will never lose its innocence. It will never magically morph into a killing machine to begin with. The "talons" seem to represent a weapon of some kind. God will never give the boy "talons," which is another way of saying humanity will never become biologically equipped for killing.