Thus Have I heard:
At one time the Blessed One was living at Rajagriha on Mount Sacred Eagle together with a great assembly of monks and laypersons. At that time the Blessed One was absorbed in a concentration concerning all phenomena that has come to be called “Profound Illumination.”
At that time also the Bodhisattva Avalokiteshvara was looking perfectly at the practie of the profound perfection of wisdom and looking correctly at the emptiness of all phenomena.
Then, through the power of the Buddha, Shariputra said to the Bodhisattva Avalokiteshvara “How should a son of the Lineage train who wishes to engage in the practice this of this wisdom?”
Thus he spoke, and Avalokiteshvara replied:
“Shariputra, whatever Son or Daughter of the Lineage who wishes to engage in this practice should realize is the emptiness of all existence; also empty are your five aggregates.
Form is empty and emptiness is form. Emptiness is not other then form and form is not other then emptiness. In the same way, the things that you are composed of, your aggregates are empty.
Shariputra, like this all phenomena are empty, having no inherent characteristics. They are not produced and do not cease. They have no taints or separation from taint. They have no increase or decrease.
Therefore, in this emptiness there is no form, no sensory input, no consciousness. There is no eye, no ear, no nose, no taste, no tactile object, no phenomenon. There is no ignorance and no ending of ignorance and so on up to no ageing, sickness and death and no ending of aging, sickness and death. Likewise empty are the four noble Truths, there is no special awareness no ‘attainment’ but also no non-attainment.
Therefore, because there is nothing to attain, Bodhisattvas rely upon and dwell in this perfection of wisdom. Their minds are always positive and feel no fear. Passing beyond delusion they attain final Nirvana. All who have attained Buddha hood are enlightened to this knowledge.
Therefore, the Mantra of the perfection of wisdom, the mantra of great knowledge, the mantra that quiets all suffering should be known as Truth. This mantra is proclaimed:
‘Tayatha Om Gate Gate Paragate Parasamgate Bodhi Soha’
Shariputra, a Bodhisattva should train himself in this way.
Then the Blessed One arose from his concentration and said to Avalokiteshvara, the Bodhisattva that he had spoken correctly: “Good, good, Son of the lineage. It is just like that. Since it is like that it is in this way the perfection of wisdom should be practiced. If you do so the Buddhas will all rejoice!
When the Blessed One had said this, Avalokiteshvara, the Bodhisattva, Shariputra and all who were present expressed delight and greatly praised what had been spoken by the Blessed One.
Here is another popular translation of The Heart Sutra
The Heart of Great Wisdom Beyond Wisdom
The great Bodhisattva Avalokiteshvara, in the deep course of wisdom beyond wisdom, seeing that the five aggregates are also empty of inherent nature, overcame all suffering and distress.
Shariputra, form is emptiness, emptiness is form. Form is not other than emptiness. Emptiness is not other than form. The same is true of feelings, perceptions, formations, and consciousness.
All phenomena are marked with emptiness. They are neither produced nor destroyed, neither defiled nor pure, neither increasing nor decreasing.
Therefore in emptiness there is no form, no feelings, no perceptions, no formations, no consciousness; no eye, no ear, no nose, no tongue, no body, no mind; no form, no sound, no smell, no taste, no touch, no object of mind; no realm of eye, no realm of mind-consciousness, nor anything in between. There is no ignorance, no extinction of ignorance, no old-age-and-death, no extinction of old-age-and-death, nor any of the twelve links.
Likewise there is no suffering, no origination, no cessation, and no path; no understanding, no attainment, and no non-attainment.
With nothing to attain the bodhisattva relies on wisdom beyond wisdom and the mind is no hindrance. Without any hindrance, there is no fear. Passing beyond every upside-down view, the bodhisattva abides in Nirvana.
All Buddhas in the past, present and future, relying on wisdom beyond wisdom, realize unsurpassed, complete, perfect enlightenment.
Therefore this is the mantra of wisdom beyond wisdom, the mantra of great knowledge, the mantra that is unsurpassed, the mantra that is equal to the unequalled, the mantra that pacifies all suffering. Free from deception, it is the simple truth:
Gate Gate Paragate Parasamgate Bodhi Svaha!
The Heart Sutra in Sanskrit