Why are these four tantras taught?
They are graded by time and caste, and powers of the mind.
The yugas are krita and treta, dvapara and kali.
Brahmins, kshatriyas, vaishyas and shudrasare the castes;
The powers are dull and average, sharp and very sharp.
Kriya chiefly teaches baths and cleansing rites.
Charya teaches that actions of the body and speech
Are equal in importance with meditations of mind.
Yoga teaches that meditation is most important.
Actions of body and speech are just accompaniments.
Anuttara is free from actions of the three gates.
There is no conceptualization of subject and object.
The ultimate concern is the luminous nature of mind.
Cleansing rites are few, or may even be discarded.
So it is said. In the former time of the perfection-having or krita age, sentient beings had no cause of manifesting the kleshas, like the inhabitants of Kurava the northern continent. Therefore, they did not depend on vows and discipline, or virtuous antidotes of mind. Purifying rites of body and speech and actions alone become the focus.
In regard to the four castes, the bhraman or priestly caste was tamed by means of rites of purification and asceticism, without engaging in others.
Those of dull powers, although they do not understand the great undertakings of mind, can see this Dharma of actions of body and speech, and enter into it. Depending on those above three purposes tantras chiefly teaching washing, rites, and purification, the kriya tantras, Amoghabaasha, and Supreme Insight (rig pa mchog), Well Established (legs par grub pa), the Appearance of the Three Worlds (‘jig rten gsum snang), etc. were taught.
Then the former krita yuga deteriorated. Since some small causes of the kleshas manifesting arose, theft and sexual intercourse came into existence, so that there were no (more) enjoyment and light. In the treta yuga, actions of body and speech were constrained, and objects of purification and rites become one of two goals. So that those of the warrior-ruler kshatriya caste, who did not perform many purification rites, might be interested in them, and intending to present teachings realizable by middling powers, upa tantras were taught, such as the Lotus Peak (padma rtse mo) and Establishing the Three Families (rigs gsum grub pa). Acts of body and speech and meditation of mind were equally taught.
In the dvapara yuga, kleshas were coarser, and mental activities of meditating on deities and so forth became the focus. For the merchant vaishya caste, which has wide interests and abilities, and composed from a viewpoint where they would be suitable to be realized by those of sharp faculties, the yoga tantras, chiefly concerned with mental meditation, with those of body and speech just as an accompaniment were taught, Abandoning the Lower Realms (ngan song sbyong ba), the Vajra Space (rdo rje dbyings) and so forth.
In this fourth age, the kali yuga, when lives are about a hundred years, the time of strife when the five denigrating corruptions run rampant, the focus is on virtues of mind alone. For low caste people or the shudra caste, who have no purifying rites at all, but do have great ascetic discipline, and to be realized by those of very sharp powers, anuttara yoga tantra, The Net of Miracles (sgyu ‘phrul dra ba), Chakrasamvara (bde mchog ‘khor lo), Guhyasamaja (gsang ba ‘dus pa) and so forth were taught. Here from a state of all actions of body, speech, and mind not being conceptualized with grasping and fixation; accepting and rejecting, asserting and denying, hope and fear and so forth are experienced as non-dual. Since the nature of mind, the greatness of primordial buddhahood exists within one, there is that great Dharma that seeks for no other buddha than that.
The Secret Practice (gsang ba grub pa) says:
For students whose time has come,
With the fortune of being tamed,
The four great styles of mantra ???
Are famed throughout the world.
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