https://www.mljtrust.org/sermons-online/acts-5-29-32/the-witness-of-the-spirit/

What empowered the early church in their proclamation of the gospel? In this sermon on Acts 5:29-32 titled “The Witness of the Spirit,” Dr. Martyn Lloyd-Jones credits it to the power of God’s Holy Spirit poured out at Pentecost upon all who believed in the gospel of Christ. This Holy Spirit made cowardly men bold in the face of death and persecution. It emboldened them and gave them the words to speak before the same Jewish leaders who had put Christ to death only a matter of days before. It is God’s Spirit that has worked in the church throughout the centuries to bring reformations and revivals. It is this Spirit that enables blind and fallen sinners to see and believe in the gospel of Christ, and this Spirit empowers Christians to live a life of holiness and love. While many today want to reject all supernatural aspects of Christianity and the Bible, the church has always believed in the God who works in the world to bring about His purposes. He does this through his Spirit and to reject the supernatural aspects of Christianity is to reject the very heart of the truth.