But you shall receive power, after the Holy Spirit has come upon you: and you shall be witnesses unto me both in Jerusalem, and in all Judea, and in Samaria, and unto the uttermost part of the earth.
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Bede
AD 735
He says, When the Holy Spirit comes upon you, it certainly will not be to bring the kingdom of Israel, or the kingdom of God to Israel, as you think, but rather it will be to furnish you the power to bear witness concerning me.
you shall be witnesses for me: He adds why this testimony is appropriate when he says in John's Gospel (15:27), because you have been with me from the beginning, that is, the beginning of my preaching and working of miracles, and so you can testify to what you have seen and heard.