In Acts 1:8, Jesus calls his disciples witnesses and calls them to go to the ends of the earth with this good news by the power of the Spirit: The Role of a Witness All Throughout Scripture Likewise, as Christians, we are called to be witnesses for Christ who present a testimony about the truth that we have experienced and heard. The witness is someone that has seen something take place and is there to tell of all that they saw, heard, and experienced. What do you think of when you hear the word “witness?” Most people probably think of someone in a courtroom.