A Course in Miracles Topic - Witness

What you witness is your interpretation of what you perceive. It is a choice which demonstrates what you believe to be true.

The world you see is but the idle witness that you were right. This witness is insane. You trained it in its testimony, and as it gave it back to you, you listened and convinced yourself that what it saw was true. You did this to yourself.     T-21.II.5:1-4.

 Perception is a choice and not a fact. ... For on the voice you choose to hear, and on the sights you choose to see, depends entirely your whole belief in what you are. Perception is a witness but to this, and never to reality. ...   Reality needs no cooperation from you to be itself. But your awareness of it needs your help, because it is your choice. Listen to what the ego says, and see what it directs you see, and it is sure that you will see yourself as tiny, vulnerable and afraid.    T-21.V.1:7,9-11/2:1-3.

Every brother you meet becomes a witness for Christ or for the ego, depending on what you perceive in him. Everyone convinces you of what you want to perceive, and of the reality of the kingdom you have chosen for your vigilance. Everything you perceive is a witness to the thought system you want to be true. Every brother has the power to release you, if you choose to be free. You cannot accept false witness of him unless you have evoked false witnesses against him. If he speaks not of Christ to you, you spoke not of Christ to him. You hear but your own voice, and if Christ speaks through you, you will hear Him. T-11.V.18:1-7.