Path of Siva
The lower path involves several supports: activities of the organs, breathing exercises, enunciation of syllables, meditation, etc., while the path of the energy rests upon the cognitive energy of the mystic. It uses this energy as a springboard, but it never quite succeeds in leaving it, ultimately hurling itself into the One.
The path of Siva is a path without support, without effort, without recourse to the faculties. It is the path of pure desire, of naked intention. It reaches toward Siva only, not toward his energy or his attributes, and it does not depend on the energy in order to propel itself toward Him. In fact, for the jnanin who follows this path, the free energy of Consciousness is inseparable from Siva. It consists of an absolute act taken of its own initiative and dependent upon no limitations.
The path of nondifferentiation (abheda), [a] devoid of distinction, determination, or particularity, is described as nirvikalpa. [b] It is without difficulty, and without actual presence, for it precedes the distinction of subject and object. And it is thus above all personal activity, such as knowing, willing, and loving.
[b. Nir = without; vikalpa = distinction. en.wikipedia.org/wiki/
This path of overcoming addresses itself solely to the ardent being full of divine Love (bhakti) who aspires only to the simple, naked Essence. The grace which he enjoys is so abundant that it takes him beyond all intellectual certitude, even without his notice. And yet it is fully apparent: Reality grasped at the very moment that it emerges, such that a powerful surge of the heart lifts him into the one Essence. [c] Without living this first moment, without holding on to the heart's vibration, one cannot possess vigilant consciousness nor be established in the undifferentiated.
[c. The author is giving her enthralled interpretation of 1,000-year-old writings.]
This surge owes its intensity to the fact that it does not encompass any division. From that moment foreward, he attains all, he knows all, is capable of all, since the totality is essentially undivided.
Since it is in the unity of this moment (the outburst) that everything is played out, it is understandable that the Siva Sutras [d, e] places great importance on the flight towards the Absolute.
The path of Siva is summarized: udyamo bhairava. "The outburst is the undifferentiated divinity," declares one of its aphorisms. (I, 5) The commentator adds: "This outburst is the emergence of the supreme illumination, the sudden flight of Consciousness in the form of an unbroken awareness of the Self, of an innate, internal fervor. As all the energies fuse within it, this outburst is bhairava – undifferentiated divine Consciousness – because it springs forth in beings who are overflowing with Love and endowed with vigilance regarding this interior Reality."
At this high level is bhakti, beyond words, the triumphant Love which forces the yogi out of himself and propels him toward the One. It has nothing in common with the love of the preceding paths that is entangled in duality. Not effusive, it is at the heart of pure aspiration, a surge of the whole being towards an inexpressible God. Blind, as it were, this flood of love nevertheless possesses a keen vigilance, not the vigilance of understanding but that of an ardent heart which withstands even reverberations of the will.
The Saivite texts compare such an outburst to a devouring flame which leaps up spontaneously and consumes forever all traces of differentiation and the last vestiges of the ego. 
All endnotes appear in a separate page: endnotes.htm Brief endnotes are reproduced in the text as footnotes (as below). Where suggested, click on the blue link to see the full endnote on the Endnotes page.
[Endnote 26. According to the description of the divine path, a single breath suffices to accomplish all; it happens that in practice, the limitations do not break apart all at once. Nevertheless, they do cease spontaneously under the pressure of renewed impulses.]
This act, the purest it could be, is completely relaxed. As soon as it appears, it is perfect and gives access to the absolute, beyond the workings of the temporal. Sudden, unforseeable, it is similar to a bolt of lightning that strikes the earth, but whose illumination does not disappear. Through it, the adorer becomes a "living liberated person." To such a person, samsara and liberation scarcely differ. The decisive realization of his essence has caused bondage to give way to total liberty.
His will, in fact, is a divine will, whole, present, effortless, with nothing of the casual or incidental, a will which is itself an imperative, not different from the infinite and sovereign energy of Siva. The word which designates it, iccha, also signifies desire, but this desire, understood as incitement, its creative source, is so absorbed by the absolute that it turns to Siva completely in an intense surge. It radically dispels all distinct apprehension, and it is raised to the divine undifferentiated Essence, free of any attribute, any quality.
Another aphorism of the Siva Sutras (I, 13) defines the nature of this very pure will as energy in its source. Iccha is described as a young virgin, Siva's Beloved... virgin because it can only be pure Subject, never an object of enjoyment, i.e., being "for someone else." She escapes contamination of the subject-object relationship. Very young, ingenuous, she acts wantonly, her play consisting of emitting and reabsorbing the universe. Perfectly detached, she nevertheless ardently gives herself to adoration of the Lord and is identified with Him. In reality, she is nothing but the supreme Energy, as inseparable from God as are rays from the Sun or heat from the Fire.
Arriving at a similar union, with all his faculties gathered at the undifferentiated Center, the yogi who is established in the infinite and virgin energy sees the Fourth state expanding spontaneously over the three other states as a tidal wave inundates all limits and levels. Through the fusion of the internal and external, he attains equanimity (samata) which he discovers at the very heart of this surge. Equanimity, in fact, no longer comes from the great conscious movement of slow leveling which characterizes the path of the energy. It is now within the very source of vision, in the first glance directed towards the Self or towards the world. A slight fluctuation is sufficient to equalize all; and in this, the yogi discovers his glorious freedom. He then declares, with Abhinavagupta:
"Oh Lord Bhairava, this consciousness of mine dances, sings, and enjoys itself thoroughly, for since it has come to possess you, the Beloved, accomplishing the one sacrifice of equality so difficult for others, is now easy." (H.A., 51)
This sacrifice, called "of the equality," finally banishes the rocky duality of becoming (samsara). The eternal and the fleeting, purity and impurity, illusion and Reality, in short, the multifaceted universe is reflected in all its splendor within the harmonious conscious Light that is always identical to itself.
The great yogi thus recovers his native glory. Its expansion brings a wonderment characteristic of the stages of this path. He contemplates all things from the immutable Center, by the light of unity, on the (inner) fascade of the universal Self.
And one treatise declares: when the faithful recognize the Self through the Self, it is within their own Self that this wonder is experienced. And Ksemaraja states that the yogi never ceases to marvel at the extraordinary and ever new magic that comes to him when he merges with undivided Consciousness. He never has enough of the uninterrupted bliss that he senses in himself. (S.S.v., I. sutra 12)
Rare is the hero whose love is spontaneous and free; when he is liberated from duality, he rejoins undifferentiated Consciousness in its initial vibration and succeeds in keeping himself there. (Bh., 40)
This path, which begins with grace, ends there in glory.  But is it not to himself that the yogi finally attributes the "very weighty"  grace that emerges from the depths of the Self. For at the heart of the will's vibration, divine incitement and human outburst coincide. On this level, grace, which is given and received in a single movement, is the essence of indeterminism.
At the end of the third chapter of the Tantraloka, dedicated to the divine path, Abhinavagupta recalls succinctly the disappearance of the contingencies which are the basis for distinction between the different paths:
"The limiting conditions appear," he writes, "as soon as Reality turns from her freedom to the external."
259. According to the Masters, the Essence transcending these limited conditions (upadhi) is dual. Either these conditions have not yet appeared or they have ceased.
260. Dual also is the way in which they cease: calmly or by a violent , spontaneous maturation characterised by an insatiable appetite, like an ardent and ceaseless fire.
[According to the commentary, the first depends upon initiations, and the teacher's veneration. The second is an intense consumption of limitations, caused by the fire of Consciousness. And, when limitations have not yet appeared, it is a question of Reality escaping by any path. The progressive disappearance of limitations takes place by the paths of activity and knowledge; sudden disappearance, by the path of Siva.]
261. The latter, that of violent maturation with its consuming the fuel of differentiation, is especially worthy of transmission.
262. All things thrown violently into the fire of our own consciousness abandon their differentiations while feeding the flame of their own energy.
263. When differentiation is dissolved by this hasty maturation, the organs that have been made divine by consciousness now savor the universe which is transformed into nectar.
264. These organs, once sated, identify their own self with the God Bhairava, the firmament of Consciousness, resting solely in the heart, Him, Fullness itself.
The Triple Aspects of the Universe's Reflection in Consciousness
268-269. The One to Whom the universe – all things in their diversity – appears as a reflection in his consciousness is the Lord of the universe. Possessing a total undifferentiated and eternally present awareness, he is the only one branded by the path of the Lord.
[This awareness of the I is fullness, for its overflow is the universe in its diversity. On this Subject, one verse states:
"However little he tastes of this flavor, he whose conduct is noble and independent knows samadhi, yoga, vows, sacred words, and recitation to be poison."]
276-277. Seeing the various levels of Reality reflected without differentiation in his own Self, he attains the nature of Bhairava. And when he sees Bhairava himself reflecting in the mirror of Consciousness, that is sublime and without artifice, he who no longer has differentiated thought spontaneously becomes Bhairava.
Having arrived at the state of Bhairava, the yogi must dominate the triple activity of emanation, maintenance, and reabsorption with respect to the universe:
280. "All proceeds from me (aham, I), all is reflected in me, and all is inseparable from me. This path of the Lord is a triple path."
The true Trika adept must become the master of these three aspects of the divine path.
1) In the form of creative emission: He is completely aware of the phonemes from A to HA when intuition springs forth: this universe emerges from me, the I (aham)."
283. "Manifesting the universe in myself, in the ether of Consciousness, I am the creator, immanent in the universe." To perceive this is to be identified with Bhairava.
2) In the form of maintenance, he recognizes: "This universe is reflected in me."
284. "All paths are reflected in me, their sustainer." Clearly, to perceive this is to be identified with the universe.
Thus, protecting the universe, he becomes its master and participates in universal Bhairava. This aspect is higher than the preceding bhairava which he discovered only in himself. At this stage, he tastes it always and everywhere since he has stamped his consciousness on the whole world.
3) In the form of reabsorption, the adept becomes aware that: "all that is me alone." Through the power of the formula of the absolute Self, he reabsorbs the universe into himself and penetrates into the peaceful state of universal Bhairava. He attains the Self in its fullness.
286. "The universe is dissolved in me, I who am full of the frenzied flames of great Consciousness." To see this is to find peace.
"I am Siva, this devouring fire which burns the dwelling into beautiful, infinitely varies elements (a dream), this flow of transmigration."
The third aspect of the divine path having been attained, the ultimate goal is also attained.
287. "The universe in its many aspects comes out of me, rests in me, and when it is dissolved, nothing more exists."
"He who sees the emanation, maintenance, and reabsorption of the universe to be indivisible because it is unified, such a person is radiant, having attained the Fourth state."
At this level, paths and procedures have no meaning:
288. "Rare are they who, purified by the supreme Lord, advance with confidence upon this Supreme path where Siva's non duality reigns."
290. "Bathing vows, bodily purifications, mental concentration, recitation of mantras, paths, oblations, recitations, samadhi, and other practices to do with differentiation have no place here."
According to the ancient Teachers:
"In truth, when the ultimate Reality is ardently desired, all means are reduced to nothingness."
Utpaladeva [f] also declares:
"Only love is worthy of appreciation in the non-illusory path of Siva. Neither yoga, nor asceticism, nor pious acts can lead to him." (I., 16)
He therefore prays to Siva: "Oh, that at every moment the inexpressible life-giving taste acquired through the repeated summonsing of Your sovereignty might increase in me, and that the majesty of yoga and of Knowledge might leave me." (VIII., 2)
How does one characterize the highly favored being who progresses along this path? The first characteristic of one endowed with intense grace is simply the divine love (bhavabhakti), with which he is filled. It is the Teacher who transmits this grace directly. His word or his example suffice to make the disciple aware of his own Essence.
"(The Teacher) initiated in the divine path is manifestly in a state to transmit supreme grace, but upon one condition: he who is to find this grace must be capable of receiving it in the manner in which it is given." Of this manner, Jayaratha comments: "just as a torch is lit from appther torch." (290-291)