Acts 1:1-3

The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach, until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen: to whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God