Why: 'in that peace, all pains are destroyed' is specific when paired with the previous verse, the pain dissolves because the reactive charge around it changed, not because circumstances did.

In life: sometimes the situation stays exactly the same and yet becomes bearable, because something in how you're holding it shifted.

Teaching: when you can't change a difficult situation, work on the charge you're carrying around it. That's often the part that's actually movable.