Perchance you saw a homeless beggar on the street one day and either felt sorry for him or ignored him. He has a body and consciousness that makes him alive just as you have but did you realize that it is parts of the same consciousness that flows through him or you or anyone else for that matter even animals, trees, bacteria, grass; everything that is life has a consciousness. Most do not realize that it is parts of the same although few mystics do. In another time or place it could be me or you that are that beggar because the condition of that consciousness that we have presently assigned to ourselves changes with time and place. It has been doing so ever since the beginning of time because material things like our bodies are born, changes and dies but consciousness is everlasting. Out of it all this was created. Not just mystics but the most learned of all scientists realize it too. As Einstein said,
A human being is a part of the whole, called by us “Universe,” a part limited in time and space. He experiences himself, his thoughts and feelings as something separate from the rest—a kind of optical delusion of his consciousness. The striving to free oneself from this delusion is the one issue of true religion. Not to nourish it but to try to overcome it is the way to reach the attainable measure of peace of mind.” Albert Einstein
Enlightened mystics that are able to free themselves from bondage of the limited self unite with the infinitely powerful and knowledgeable infinite to different degrees as long as they are centered in a finite body. For the ordinary human, it is important to realize that when we do a good thing for ourselves we do it for our limited self but when we do a good deed for another it is to our inner deeper self, a greater more powerful good and even though we do not see it clearly, it is the source from which our feeling arise and we are filled with happiness. The converse is also true when we harm another living thing be it an insect or be it a tree. When our consciousness gets totally confined to our limited self as when charged with greed, lust, ego or anger then we become most ignorant and stupid. Conversely a mystic is so full of knowledge that even his casual utterances are prophecies when about future.
Image before some modifications here from: http://www.free-pictures-online.com/