Matt Brown emphasizes the significance of small gospel acts in changing the world, drawing inspiration from the story of Philip in Acts 8. He highlights that every Christian is called to share the hope of Jesus with those around them, regardless of their circumstances. Brown encourages believers to live with eternity's values in view and to be passionate about reaching those who are far from God. He illustrates how Philip's obedience to the Holy Spirit led to the conversion of the Ethiopian eunuch, which ultimately impacted an entire nation. The sermon calls for Christians to recognize the power of their everyday interactions and the potential for small acts of faith to create lasting change.