A.B. Simpson explores Isaiah's call and consecration, emphasizing the profound impact of King Uzziah's death on Isaiah's vision of God. In a time of despair, Isaiah sees the Lord high and lifted up, which transforms his understanding of service and humility. The sermon highlights the necessity of experiencing personal brokenness and cleansing before one can effectively serve God. Simpson draws parallels between Isaiah's experience and the challenges faced by modern believers, urging them to seek God's vision amidst their shattered dreams. Ultimately, the message culminates in the call to service, encouraging believers to respond to God's invitation with a willing heart.