"Nothing to be attained" is the all-important theme of the Sutra. The obstruction alluded to in the above sentence refers to the three obstructions of function, to wit: 1) The karmic obstruction, or the obstruction of deeds done in the past; 2) the obstruction of retribution; 3) the obstruction of passion.

The above quote implies that the supramundane Void is the True Existence of all dharmas, and for that same reason no dharmas can be obtained. Since the Bodhisattva cannot seek outside help when dealing with obstructions, he has to rely on insights provided by his own radiant wisdom for his attainment of freedom. The first to be eliminated is the obstruction of retribution, which is of two kinds: the dependent has already discarded these two kinds of obstruction, and the different sorts of anxiety have all vanished from his mind.

This clause is about discarding obstruction to action. Not to be obstructed by body and mind means to be free of worry and fear. The practice of Bodhisattva action engenders five kinds of fear, and those who have not yet broken off delusion and who are in the early stages of the Bodhisattva career are particularly susceptible: 1) fear of being left without sustenance after giving away all possessions; 2) fear of being insignificant after giving up one's reputation of accomplishment; 3) fear of dying in situations that call for self-sacrifice; 4) fear of falling into evil circumstances; 5) fear of addressing an assembly, especially one with important people present. These five fears, then, obstruct Dharma practice, and without them there is no more obstruction to action.

This statement is related to the obstacle, or obstruction, of passion. That obstruction has its root in the defilement of confusion, or ignorance, which manifests as mistaking the impermanent for the permanent, the ugly for the beautiful, and suffering for happiness. It is the way of people of mundane interests. The Bodhisattva, however, whose conception has been clarified through Prajna has been liberated to a great extent from that obstruction.

When there is no more mental pain or grief, Nirvana becomes perceptible, comprehensible, inviting and attractive. It is the complete and final cessation of greed and craving, hatred and ignorance and, therefore, the cessation of rebirth and of the continuity of life. Then, the Dharmakaya, Prajna and, consequently, Freedom manifest themselves to their fullest. Nirvana cannot be expressed through words; it has to be experienced.

In this sentence, Prajna is proclaimed to be the perfect, ultimate Dharma of supreme relevance not only to Bodhisattvas but to all the past, present and future Buddhas as well.

The above segment of The Heart Sutra praises the merits of Prajna. The term spell suggests that the theme and the essence of this sutra transcend all intellectual concept; its power and its strength are operative in realms not amenable to manipulation. Furthermore, its effect can manifest itself instantaneously, transcending the worldly, attaining holiness.

The above is a mantra, which is an esoteric teaching by means of which we are reminded of the subtlety and complexity of the inconceivable Dharma. The body of Teachings includes some exoteric parts, such as the sutras, and some esoteric ones, such as the dharanis, or mantras. Exoteric Teachings are accessible to rational understanding and can be explained, but the meanings of the esoteric or mystic forms of prayer, such as dharanis, or mantras, are not within the reach of the intellect; thus, the good is upheld and cannot be lost nor can evil arise. During recitation, dharanis, or mantras, enable the one reciting them to control both the sound and the timing, but any recognizable words and meanings which would normally hold his or her mind captive are not there. One then has an opportunity to experience expansiveness, or spaciousness, of mind, one of its very special characteristics.

To recite the above mantra by itself, omitting the text of the Sutra, is a true Mahayana practice of the non-discriminating mind. The inconceivable nature of the Teaching is apprehended and the teaching seen as a whole. Through study, the Sutra and a complete understanding of it equal the meaning implied in the mantra (sometimes referred to as spell).

This explication of The Heart Sutra, including both the exoteric and the esoteric aspects, is presently completed. As a final word, let me caution that any contrived or faulty interpretations of the Teachings ought to be carefully avoided.