Zac Poonen emphasizes that the quality of our life, defined by fulfilling God's will, is far more important than its length. He illustrates that some can accomplish God's tasks in a shorter time than others, and that our earthly lifespan is predetermined by God, not by human standards. Poonen warns against the folly of seeking to extend life unnecessarily, as seen in Hezekiah's case, and encourages acceptance of God's will regarding our time on earth. He highlights that while we can pray for longevity, it should be with the intention of serving God more effectively. Ultimately, our focus should be on living a life that glorifies God through obedience and purpose.