... the non-dual Kashmir Shaiva tradition considers the empowering of the mantra by the enlightened consciousness of the teacher as the essential feature of the mantra... it is only then that the mantra is considered to be ... effective... The various mantric "sounds" written in books, engraved in sculpture, or casually spoken are, therefore, not technically mantra-s {since they haven't been empowered by the guru during the spiritual aspirant's initiation}.
In addition to the mantra and the process of initiation, there is always someone who performs the initiation. This "other" who initiates may be a human guru or it may be Shiva himself. In fact, the guru is always taken to be Shiva incarnate by reason of his condition of enlightenment. However there are occurrences of a kind of spontaneous initiation by the "inner" guru of the Heart who may appear to the {spiritual aspirant} in a vision or a dream and initiate him into the use of the appropriate mantra. Even here, however, where there is no apparent "external" teacher, inititation is effected by a higher power which is experienced by the {spiritual aspirant} as other than himself. Abhinavagupta makes reference to this process of spontaneous initiation in the Tantraloka, and describes a direct process of learning from the great Lord who resides in the Heart...
(pp. 164-5)
It is ... as a result of his condition of realization that the guru is considered to be an authoritative teacher. That is to say, even if the guru is not learned in the sacred scriptures, his condition as a realized being awakens within him a perfect knowledge of the meaning of all the sacred scriptures. As a result, the primary characteristics of the guru are the achieved condition of realization, which he lives on a day-to-day basis, and his capacity to transmit realization directly to his disciples. Moreover, it is precisely this type of teacher, known as the "spontaneously-perfected" teacher ... who seems to have been preferred by Abhinavagupta and the Kaula tradition. This sort of teacher was preferred because he was thought to have been initiated directly by the Goddess of his own consciousness.
(p. 165)
The face-to-face meeting of the disciple and the guru does not represent merely an encounter between two separate beings, one of whom happens to be enlightened and can thus aid and help the other in the search for enlightenment. Rather, by entering into a relationship of service the disciple places his finite awareness in direct confrontation with the enlightened consciousness of the guru, which is the same unbounded consciousness the disciple wishes to attain. This meeting of the finite and infinite modes of counsciousness represents the very condition of vimarsha, of consciousness doubled back on itself... As the disciple comes face to face with the guru, his finite consciousness encounters its own powerful and expanded source in the person of the teacher. In this situation, and without any conscious effort on his part, the disciple activates within himself the kaulika function. In this way devotion to the teacher represents the ideal spiritual posture for the disciple. It replicates, both externally in the personal connection established, and internally in terms of the inner meditative current that is released, the liberating, graceful, and self-referential nature of the unbounded consciousness of Shiva.
(p. 165-166)
... gurupaya, may also be read as stating, "the method itself is the teacher." In this reading the implication seems to be that the method is the only teacher necessary. Once the disciple has been initiated into the method by the human guru, the very presence of the Heart-mantra in his awareness is thought to be enough to elicit from consciousness itself, or from the guru in the Heart, all the direction, guidance, and knowledge that is necessary for the satisfactory attainment of the goal of the path, the condition of freedom in life (jivan-mukti).
(p. 166)