John Gill preaches on the miraculous conception and birth of the Messiah, emphasizing the fulfillment of prophecies that declare the Messiah would be born of a virgin, as foretold in Isaiah 7:14. He argues that this extraordinary event is a sign of God's divine intervention and a source of hope for the house of David amidst their fears. Gill further explains that the birth of Jesus Christ was a literal fulfillment of these prophecies, countering Jewish objections and affirming the uniqueness of the Messiah's incarnation. He highlights the significance of the virgin birth as a miraculous act of God, ensuring that Jesus was both fully divine and fully human, suitable to be our Savior. The sermon concludes by affirming the ongoing relevance of these prophecies and the assurance they provide to believers.