What is it that prevents enlightenment? We may understand the spiritual theory but still feel like we are a long way off from being enlightened. We may understand Non-Duality and know that there is only One, an Infinite Indivisible One. We may understand that concepts, labels and forms can never truly be defined. We may recognise that there are no limits, and there isn't a multiplicity. We may understand that this means we are not the separate identity that the mind thinks we are. We may grasp the teaching that identity is thought-based, and thoughts appear and disappear in the Awareness or Consciousness or What Is, and we know that we are That. But this knowledge, no matter how thorough it is, doesn't make us enlightened.
So what is it that is stopping enlightenment if I know and believe all the theory? It's the separate self, or rather the sense of being a separate self. It can't really be defined, because it's not real, it's a thought-based identity. Let's call it the ego. It's the ego that thinks it knows all this. It's the ego that claims it is the one who knows and believes Non-Duality theory. It's the ego that wants to be enlightened, or at least wants to find peace and contentment. But the ego generally values its identity too much. Without its identity it is nothing. If it lets go of its sense of self then it effectively dies or disappears. Enlightenment is the death of the ego, the end of the separate self that never really was. It is the ego that feels the need for enlightenment and the ego that prevents enlightenment. Kind of.
The 'kind of' issue is that the ego doesn't really prevent the enlightened state. The enlightened state is here already. It is the natural unlimited, undefined state of being. The ego is the sense and belief that it is a defined and limited being. So although the ego may claim the knowledge that there is no separation, the ego is still waving its flag of identity whilst it does so: "I know that there is no separate me!" This is where the issue lies.
The separate self cannot attain enlightenment. Only in making the ultimate sacrifice of itself is the enlightened state revealed. This means the death of separate identity, not death of the body. Some call the enlightened state the Kingdom of Heaven. It is the placeless place where there are no limits, there is only Freedom. The separate self cannot enter. It needs to discard its limits and its definitions of itself, which is what makes it a seemingly separate self. Only then, when there is no ego, is the Kingdom of Heaven revealed to be always here. Paradise is right here. Freedom, Peace, Love and Contentment is right here in the natural state of being. It is hidden or missed because of the ego's ignorance to it. The ego itself is the ignorance of the infinite indivisible nature of Reality.
The knowledge that we gain can only point to What Is. Knowing about Reality is not enough. We need to loosen and drop the identity of the one who claims to know it. This can take time and effort. The ego needs to work at unravelling itself, using the knowledge and practices learnt. Self Enquiry seeks out the source and nature of the identity, and realises that it is illusory and non-existent. The Infinite One is all. Worship and service to the whole lessens the strength of the ego identity, till the devotee is lost in the Infinite One.
Who realises this? No-one. Reality is an Infinite Singularity. It has no true accurate name or definition. It is no-one, yet all appear within it. It is Nothing yet Everything.