Acts 1:4-8

4 Being assembled together with them, he charged them, “Don't depart from Jerusalem, but wait for the promise of the Father, which you heard from me.  5 For John indeed baptized in water, but you will be baptized in the Holy Spirit not many days from now.”

6 Therefore, when they had come together, they asked him, "Lord, are you now restoring the kingdom to Israel?"

7 He said to them, “It isn't for you to know times or seasons which the Father has set within His own authority.  8 But you will receive power when the Holy Spirit has come upon you. You will be witnesses to me in Jerusalem, in all Judea and Samaria, and to the uttermost parts of the earth.”

Matthew 16:1-4

1 The Pharisees and Sadducees came, and testing him, asked him to show them a sign from heaven.  2 But he answered them, “When it is evening, you say, 'It will be fair weather, for the sky is red.'  3 In the morning, 'It will be foul weather today, for the sky is red and threatening.' Hypocrites! You know how to discern the appearance of the sky, but you can't discern the signs of the times!  4 An evil and adulterous generation seeks after a sign, and there will be no sign given to it, except the sign of the prophet Jonah.”  He left them, and departed.