18. Some general comments from Acts 1:2-5 In these various appearances (and possibly others, not mentioned), which were all over a period of 40 days, Jesus gave many convincing proofs that he was alive, and spoke about the kingdom of God. On one occasion, while he was eating with them, he gave them this command: "Do not leave Jerusalem, but wait for the gift my Father promised, which you have heard me speak about. For John baptized with water, but in a few days you will be baptized with the Holy Spirit."