Peter Brandon emphasizes the significance of the resurrection of Christ as the foundation for the belief in a new body, highlighting that Christianity is rooted in historical evidence rather than emotions. He explains the logic behind the necessity of a new body, contrasting our current 'body of humiliation' with the promised 'body of glory' that believers will receive. Brandon illustrates that just as Christ was raised as the firstfruits, believers will also be transformed, and he encourages the congregation to understand the earnest of the Holy Spirit as a foretaste of the glory to come. He concludes by affirming that the resurrection is not just a theological concept but a transformative reality that assures believers of their eternal hope.