Zac Poonen emphasizes that God relies on broken individuals to fulfill His purposes on Earth, using the life of Moses as a prime example. He illustrates how Moses' early life in Pharaoh's palace, despite his education and abilities, did not prepare him for God's work until he underwent 40 years of humbling experiences in the wilderness. Poonen warns that many Christians mistakenly believe that their talents and knowledge qualify them for service, but true readiness comes through brokenness and submission to God's will. He encourages believers to embrace the challenges and circumstances God places in their lives, as these are essential for spiritual growth and preparation for His calling.