Acts 1:4-8

And while being in their company and eating with them, He commanded them not to leave Jerusalem but to wait for what the Father had promised, Of which [He said] you have heard Me speak. [John 14:16, 26; 15:26.] For John baptized with water, but not many days from now you shall be baptized with (placed in, introduced into) the Holy Spirit. So when they were assembled, they asked Him, Lord, is this the time when You will reestablish the kingdom and restore it to Israel? He said to them, It is not for you to become acquainted with and know what time brings [the things and events of time and their definite periods] or fixed years and seasons (their critical niche in time), which the Father has appointed (fixed and reserved) by His own choice and authority and personal power. But you shall receive power (ability, efficiency, and might) when the Holy Spirit has come upon you, and you shall be My witnesses in Jerusalem and all Judea and Samaria and to the ends (the very bounds) of the earth.