E and VAM
(from Light of Wisdom, Vol. 1, pgs. 28-29 et al)
Related to the general meaning of Mantrayana, "wisdom" is the support, the mandala, while "essence" is the supported, the circle of deities. This is expalined in the Two Segments:
"Center" or manda means "essence" or sara, while la means "to take hold of" and therefore to capture the essence. Thus they explain the meaning of the word mandala. The "center" of the aggregates, elements, and sense-bases describes the "essence" kunda. This is the relative bodhichitta which forms the basis for great bliss. Taking hold of or capturing it by means of the (tummo practice of) blazing and dripping is explained as the hidden meaning of mandala.
Alternately, the essence of all teachings describes the view of the Middle Way. This is the ultimate bodhichitta, free from constructs, which is natural great bliss and compassion. Taking hold of or capturing it by means of actually practicing their unity is expalined as the general meaning of mandala. Their merging, or the combination of word and meaning, expresses mandala itself.
Furthermore, "center" means that the natures of these aggregates, elements, sense-bases and objects, and disturbing emotions are the five families of male and female buddhas and the goddesses. "Circle" means cutting through the defilements.
In the context of the common development and completion, mandala means the support and the supported, while in the context of the completion stage by itself, mandala means the union of emptiness and compassion. (JOKYAB)
The meaning of that describes the path of the development stage as well as its associated points.
So, according to the hidden meaning, "wisdom" is the support, the syllable E of primordial great emptiness. "Essence" is the supported, the VAM syllable of great bliss. The Exposition Tantra of Guhyasamaja states:
Since omniscience abides
In the magical display of these two letters E and VAM,
E and VAM are fully expalined
At the beginning of teaching sacred Dharma.
(Note: The Exposition Tantra of Guhyasamaja is also called the Vajra Garland. (JOKYAB)
To explain this quotation: E and VAM are the union (dbyer med) of bliss and emptiness, emptiness and compassion, and of means and knowledge. Since the coemergent wisdom of the omniscience of all the buddhas abides in the magical display of the union of these two syllables of means and knowledge, the E syllable of great emptiness and VAM syllable of great bliss, the syllables E and VAM are fully explained during the opening chapter at the beginning of teaching the profound and extensive aspects of the sacred Dharma. DKR
The Vajra Garland adds:
E is emptiness, it is taught.
Likewise, VAM is compassion.
The bindu results from their union.
This union is the supreme marvel
Embracing these 84,000 Dharma teachings.
In short, this is the seal of the Dharma.
As thus stated here and in countless other places, these two syllables E and VAM provide the setting for teaching all the sutras and tantras, and therefore the profound and vast meaning can be elaborated from them.
According to the hidden conventional truth of the system of Phakshab, E and VAM mean the body of unity which manifests from luminous wisdom as its essence after the stages of illusory body have been perfected.
According to the concealed teachings on passion, when following what has been taught in the Ocean of Magical Display and elsewhere, the nadi-wheels are the syllable E and the bindus are the syllable VAM, and thus these apply to the liberation of the upper gate. Moreover, the lotus of the consort is E and the lord's vajra is VAM, and thus these apply to the secret lower gate. The meaning of these points will be explained in this text.
According to the ultimate meaning, "wisdom" is the original space of primordial purity, and "essence" is spontaneous presence, the "vajra chain of awareness." Thus these mean the indivisible unity of space and awareness, the ultimate realization of the Original Protector.