You are only able to leave the cycle of reincarnation when you can thoroughly understand the original nature of mind, realize the truth of emptiness and comprehend the nonexistence of a real self in human beings. It is futile to cultivate concentration if you do not know or have a concept of your original nature. If you only seek realization and do not have this understanding, you will not even know what it is you are supposed to realize. You will simply enter into a state of mental confusion. Even if, upon reflection and introspection, your original nature suddenly manifests before you, you will still not recognize it. However, it is through the practice of concentration that you can thoroughly understand the original nature of mind. To realize the truth concerning your original nature, you must go from understanding to vision, from vision to penetration, from penetration to realization. You must have a working model or concept about what you are looking for to proceed. Knowing the principles or concepts involved, which is the starting point, is not the same thing as realizing your original nature. Your original nature is the pure dharma body of all sentient beings within the three spheres of existence (triloka). It is united with the universe. It has no form or shape, no physical body or appearance. All living beings possess this original nature equally. It is the same as the dharma body of the Tathagata or dharmakaya. It does not come and does not go. It is not too much nor is it lacking. It is immaculate (not clean or not dirty). The dharma body realized by living beings has just not reached the level of perfect realization attained by the Buddhas, but it is not different. This concept is sometimes called Buddha-nature, dharmakaya, wonderful prajna wisdom, etc. as well as original nature. To understand principles regarding the emptiness of one’s original nature and what wonderful prajna wisdom is, one should study the 600 volumes of the Great Prajna Sutras by reading Expounding the Absolute Truth through the Heart Sutra by H.H. Dorje Chang Buddha III.