Acts 1:3-4

³With abundant proofs, he showed himself to them, still living, after his death; appearing to them from time to time during forty days, and speaking of all that related to the kingdom of God.

⁴And once, when he had gathered them together, he charged them not to leave Jerusalem, but to wait there for the fulfilment of the Father's promise — “that promise,” he said, “of which you have heard me speak;