Being a witness implies an activity of some sort–something has to be witnessed. Receiving the witness from the Holy Spirit is no different. In this case, the activity that needs to occur is our “self-will” needs to step aside. Don’t be like the tall person standing in front of you at an event you want to see (witness), you move to one side to look around them, they move to that side, you go to the other, they go to the other, you stand on tippy toe, they’re too tall, you jump up and down and get out of breath . . . basically, you miss the whole event because of the tall person. That “tall person” is YOU standing in front of the Spirit of God in you. God does not “recognize” that tall YOU, so SIT DOWN!
Receive the power of a reliable witness–the Testimony of Jesus Christ within you. I love this verse–“The Spirit Himself bears witness with our spirit . . . ” (Romans 8:16). The whole point here is, “our spirit” here has a capital S, not a small s.