As Atman, you must look backwards, inwards towards Brahman (God) to merge with your Source. Once this is done, the mind is guided by the true Self.
If you as Atman are continually looking or projecting your attention forwards to and within mind a false sense of Self is born called Ego, that in turn veils the true Self. When this happens, we live at the level of Mind, with Mind dictating to Atman. In other words we stop being master of the Mind and instead become its servant.
Whatever way Atman (Christ or Buddha) is facing, is what Atman becomes: either the true Self or Ego.
Be sure that as Atman (The Witness) you do not imagine looking inwards towards and as Brahman (away from Mind), for this is using the Mind. Do not imagine with the mind 'looking backwards.' If you feel your attention as Mind, stretching towards something, then take this as an indication that you are using the mind which activates Mind. The mind must remain still.
Rather Let the I of Thy Self as Atman dissolve into and as Brahman through marinating in the utter stillness of your 'I am-ness'. This will feel like a stillness, rather than a stretching of mind, that will eventually collapse into itself.
Put another way, concentrate on your sense of I am-ness. Hold that thought - hold that state of mind, for as long as you can. Keep doing that.
Eventually through continual practice of focusing your I on the I of Brahman, your I will open up - revealing the fullness of your Being.
~ Love Tracy
Sri Ramana Maharshi explains it here: