Chuck Smith discusses the severe judgment faced by Nadab and Abihu for offering 'strange fire' before the Lord, emphasizing that God desires service that originates from His own kindling. He explains that the priesthood was chosen to represent God accurately, and any corruption within it could mislead the people. Smith warns against motivations that are not aligned with God's will, highlighting the importance of serving with a clear mind and pure heart. He also points out that many today may be offering strange fire through gimmicks rather than genuine worship, urging believers to focus on glorifying God rather than seeking personal attention.