 After that the Holy Ghost has come upon you, and ye shall be witnesses unto me." So our Savior gave the church both a promise and a mission to accomplish, and the promise was that the Holy Spirit would come and that He would energize the disciples to fulfill the mission of reaching the world with the gospel. And then as you read chapter 3 in Acts, you find that power on full display as God's Holy Spirit allowed Peter to heal a lame man.