But you will receive power when the Holy Spirit has come upon you, and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the farthest parts of the earth."

This Jesus God raised up, and we are all witnesses of it.

We are witnesses of all the things he did both in Judea and in Jerusalem. They killed him by hanging him on a tree,

and for many days he appeared to those who had accompanied him from Galilee to Jerusalem. These are now his witnesses to the people.

and repentance for the forgiveness of sins would be proclaimed in his name to all nations, beginning from Jerusalem.

and you also will testify, because you have been with me from the beginning.

This is the third time I am coming to visit you. By the testimony of two or three witnesses every matter will be established.

how will we escape if we neglect such a great salvation? It was first communicated through the Lord and was confirmed to us by those who heard him,

And so

When the Advocate comes, whom I will send you from the Father -- the Spirit of truth who goes out from the Father -- he will testify about me,

But I tell you the truth, it is to your advantage that I am going away. For if I do not go away, the Advocate will not come to you, but if I go, I will send him to you.

while God confirmed their witness with signs and wonders and various miracles and gifts of the Holy Spirit distributed according to his will.

They were shown that they were serving not themselves but you, in regard to the things now announced to you through those who proclaimed the gospel to you by the Holy Spirit sent from heaven -- things angels long to catch a glimpse of.

Whom

All of them were filled with the Holy Spirit, and they began to speak in other languages as the Spirit enabled them.

While Peter was still speaking these words, the Holy Spirit fell on all those who heard the message.

(Now he said this about the Spirit, whom those who believed in him were going to receive, for the Spirit had not yet been given, because Jesus was not yet glorified.)

General references

But when they bring you before the synagogues, the rulers, and the authorities, do not worry about how you should make your defense or what you should say,

You are witnesses of these things.