Acts 1:1-11 (NASB)

1 The first account I composed, Theophilus, about all that Jesus began to do and teach, 2 until the day when He was taken up to heaven, after He had by the Holy Spirit given orders to the apostles whom He had chosen. 3 To these He also presented Himself alive after His suffering, by many convincing proofs, appearing to them over a period of forty days and speaking of the things concerning the kingdom of God. 4 Gathering them together, He commanded them not to leave Jerusalem, but to wait for what the Father had promised, “Which,” He said, “you heard of from Me; 5 for John baptized with water, but you will be baptized with the Holy Spirit not many days from now.”

6 So when they had come together, they were asking Him, saying, “Lord, is it at this time You are restoring the kingdom to Israel?” 7 He said to them, “It is not for you to know times or epochs which the Father has fixed by His own authority; 8 but you will receive power when the Holy Spirit has come upon you; and you shall be My witnesses both in Jerusalem, and in all Judea and Samaria, and even to the remotest part of the earth.”