Within this world, the most powerful obstacle or negativity is known as the grasping of self, the "I", or theego.
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When one just thinks of "I" and has that kind of strong ego and pride, then within that kind ofmind-stream it is very difficult to have any dharma teachings and practices. Pride or the ego is like an iron ball which pulls us down.
If we carefully investigate ourselves, we will not find an "I" existing in reality. We think, "I am," and "He is," or "She is," but when we examine truly, these are not existing in an absolute sense. For example, we may think of our body as "I," but when we investigate we can see that the body is not the "I." The "I" feels happy, the "I" suffers, the "I" has this pain and sickness, and then the "I" dies. But when at death the five-aggregatesof our physical bodies die, still our external body is there, but it no longer has all those kinds of experiences of happiness or pain. For example, when the dead body burns in the fire, it does not feel the heat at all. When it is buried under the ground, there is not any kind of feeling either. Even when it is eaten by dogs and vultures, there is no pain at all. When death happens, all the pains and sufferings associated with the body are no longer there.