The central message of this sermon is that God's holiness and perfection require the payment of humanity's debt to Him due to sin, which cannot be written off or transferred but must be satisfied through sacrifice. This debt is discharged through Christ's death on the cross, where He pays the price for humanity's sin, fulfilling the type of the Passover lamb. The sermon advances the belief that God's justice and mercy are not mutually exclusive, but rather can coexist in His character as He provides a way to reconcile humanity with Himself. The takeaway is that Christ's sacrifice was necessary to pay the debt of humanity's sin, and this understanding helps to appreciate the significance of the Passover lamb as a type of Christ.