From A Course In Miracles:
“The ego has a strange notion of time, and it is with this notion that your questioning might well begin. The ego invests heavily in the past, and in the end believes that the past is the only aspect of time that is meaningful. Remember that its emphasis on guilt enables it to ensure its continuity by making the future like the past, and thus avoiding the present. By the notion of paying for the past with the future, the past becomes the determiner of the future, making them continuous without an intervening present. For the ego regards the present only as a brief transition to the future, in which it brings the past to the future by interpreting the present in past terms.
“’Now’ has no meaning to the ego. The present merely reminds it of past hurts, and it reacts to the present as if it were the past. The ego cannot tolerate release from the past, and although the past is over, the ego tries to preserve its image by responding as if it were the present. It dictates your reactions to those you meet in the present from a past reference point, obscuring their present reality. In effect, if you follow the ego’s dictates you will react to your brother as though he were someone else, and this will surely prevent you from recognizing him as he is. And you will receive messages from him out of your own past because, by making it real in the present you are forbidding yourself to let it go. You thus deny yourself the message of release that every brother offers you now.
“The shadowy figures from the past are precisely what you must escape. They are not real, and have no hold over you unless you bring them with you. They carry the spots of pain in your mind, directing you to attack in the present in retaliation for a past that is no more. And this decision is one of future pain. Unless you learn that past pain is an illusion, you are choosing a future of illusions and losing the many opportunities you could find for release in the present. The ego would preserve your nightmares, and prevent you from awakening and understanding they are past…
…”If you accept your function in the world of time as one of healing, you will emphasize only the aspect of time in which healing can occur. Healing cannot be accomplished in the past. It must be accomplished in the present to release the future. This interpretation ties the future to the present, and extends the present rather than the past. But if you interpret your function as destruction, you will lose sight of the present and hold on to the past to ensure a destructive future. And time will be as you interpret it, for of itself it is nothing.”