"But you shall receive power when the Holy Spirit has come upon you; and you shall be witnesses to Me in Jerusalem, and in all Judea and Samaria, and to the end of the earth." —Acts 1:8
When Alfred Nobel discovered an explosive element that was stronger than anything the world had known at the time, he asked a friend and Greek scholar for a word that conveyed the meaning of explosive power. The Greek word was dunamis, and Nobel named his invention "dynamite."
Dunamis is the same word that Jesus used when He told His disciples, "But you shall receive power when the Holy Spirit has come upon you; and you shall be witnesses to Me in Jerusalem, and in all Judea and Samaria, and to the end of the earth" (Acts 1:8). In other words, "You shall receive explosive, dynamite power when the Holy Spirit has come upon you."
Think about how this power transformed the first-century believers. Prior to Pentecost, Simon Peter couldn't stand up for his faith when strangers asked him if he was a follower of Jesus. After the power of the Holy Spirit was poured out on Pentecost, Peter stood up and boldly preached the gospel, resulting in 3,000 people being saved.
After Saul of Tarsus became a believer on the Damascus Road, God led Ananias to go and pray for him. He was then filled with the Holy Spirit, and from that moment on, he went out and proclaimed Christ in the synagogues.
This power is for a purpose. It is not power to be crazy or power to do weird things. It is power to be a witness . . . power to have the courage to tell someone about Jesus Christ . . . power to tell people about what Jesus has done for you.