Do not worry about what to say or how to say it. At that time you will be given what to say, for it will not be you speaking, but the Spirit of your Father speaking through you.
Matthew 10:19-20
But you will receive power when the Holy Spirit comes on you; and you will be my witnesses in Jerusalem, and in all Judea and Samaria, and to the ends of the earth.
Acts 1:8
See also Luke 24:48-49; Acts 2:11; 4:8-13; 5:27-32.
Another feature of the Spirit's work is to help us in our witnessing to Jesus. The streams of living water that Jesus promised ( John 7:38) are meant to flow from us, not stay within us! Not all of us are evangelists; but all of us can, and should, be witnesses.
God tells us in the bible as to what we should do:
For we cannot help speaking about what we have seen and heard.
Acts 4:20
See also Luke 7:16-17; 8:38-39; John 9:25
Witnessing is not only by telling people what we see God does, and what God says, witnessing is also being kind to others, caring even for those that do not know us, we are a witness in our actions, and in the way we talk and the way we handle different situations.
Chrissie