John Gill emphasizes the pivotal role of the Son of God in the covenant of grace, asserting that Christ is not only the mediator but also the very essence of the covenant itself. He highlights that Christ's willingness to fulfill the Father's will is expressed in His incarnation and sacrificial death, which were preordained in the covenant. Gill points out that all blessings and promises are realized in Christ, who is the representative head of His people, fulfilling the law and making atonement for sin. The sermon underscores the importance of Christ's consent to the covenant, as seen in His declaration to do the Father's will, which is foundational to the Christian faith. Ultimately, Gill illustrates that Christ's actions confirm His commitment to the covenant, ensuring the redemption of His people.