The word not to be added to or cut from is the desired state itself, taken as it is and occupied fully rather than tinkered with and deferred. To add is to keep improving the wish, to diminish is to shrink it toward what seems reasonable, and both are ways of refusing to live in it now. Keeping the commandment is simply dwelling in the assumption exactly as given, whole and unedited.
Behind this stands the single loyalty that matters, service to I AM alone rather than to any outside power. A person reaches the fulfillment he wants by inhabiting the state cleanly, neither padding it nor bargaining it down. The state assumed and felt as already so is the word that must be kept intact. A wish left exactly as desired, and lived in, is a wish already on its way to fact.