«نهبت من الأعمار ما لو حويته»
You seized so many lifetimes that, were you to possess them…
«لهنت الدنيا بأنك خالد»
The world could rejoice at your remaining alive forever.
The first praise depicts courage in the exaggerated image of taking enemies' years. The second imagines those years added to the praised person's own lifespan, making his continued existence a cause for the world's happiness.
Thus valor gives rise to the additional praise that his enduring life would benefit the world. The hyperbole supports the rhetorical entailment.