Acts 1:1-5 - The Preface
1 I indeed made the former treatise, O Theophilus, about all things that Jesus began both to do and to teach, 2 until a day in which he was taken up, having commanded, through Holy Spirit, the apostles whom he chose, 3 to whom he also presented himself living, after his suffering, by many infallible proofs, being seen by them during forty days, and speaking the things about the kingdom of God.
4 And being assembled together, he commanded them not to depart from Jerusalem, but to wait for the promise of the Father, Which, he said, ye heard from me. 5 Because John indeed immersed in water, but ye will be immersed in Holy Spirit after not many of these days.