The sermon centers on the identity and divine calling of the Christian community, portrayed as a living letter written not on stone but on the hearts of believers by the Holy Spirit. Paul defends his apostleship not through external credentials, but by pointing to the Corinthians themselves as evidence of authentic spiritual transformation—proof that Christ is writing His message through them by the Spirit's power. This identity as a letter of Christ and the Spirit underscores the new covenant's essence: not a legalistic code, but a life-giving relationship where God's grace replaces human sufficiency. The preacher emphasizes that true spiritual effectiveness arises not from personal strength, but from acknowledging one's insufficiency and relying wholly on God's enabling grace. Ultimately, believers are called to live as visible, transformative testimonies of Christ's presence, reflecting His character and drawing others to Him through the Spirit's work in their lives.
