Not merely by knowing that alone will you be liberated; the phrase 'by knowing alone' refers to the sense of the karmic subject. Elsewhere the Lord says: without knowing whose action, non-action, or mixed action it is, how could one see the vision, and from where liberation? Non-action (akarma) is the cause in some sense; actions, non-actions and mixed actions are prohibited because binding. Therefore one must distinguish action and so on. Even those under curses are not able to know this quickly; hence the statement 'this is deep'.