Acts 1:1-5
The Promise of the Holy Spirit
1:1 In the first book, O Theophilus, I have dealt with all that Jesus began to do and teach, 2 until the day when he was taken up, after he had given commands through the Holy Spirit to the apostles whom he had chosen. 3 He presented himself alive to them after his suffering by many proofs, appearing to them during forty days and speaking about the kingdom of God.
4 And while staying with them he ordered them not to depart from Jerusalem, but to wait for the promise of the Father, which, he said, “you heard from me; 5 for John baptized with water, but you will be baptized with the Holy Spirit not many days from now.”
(ESV)