What is the correct mantra to be practiced by a sādhaka following the traditional path? I suggest referring to one śloka from the Gurugītā:
ध्यानमूलं गुरुर्मूर्तिः पूजामूलं गुरुर्पदम् ।
मन्त्रमूलं गुरुर्वाक्यं मोक्षमूलं गुरूर्कृपा ॥
dhyānamūlaṁ gurormūrtiḥ pūjāmūlaṁ gurupadam |
mantramūlaṁ guruvākyaṁ mokṣamūlaṁ gurukṛpā ||
The image of the Guru is the basis of meditation,
The feet of the Guru is the basis of worship,
The basis of mantra is Guru’s speech,
The basis of liberation is Guru’s grace.
It may seem to someone that this is said for a beautiful word, but in reality it is not. In deed, as it is said in this śloka, it is so. However, the meaning of this śloka lies in the correct attitude towards the guru, which is not characteristic of many, especially in the Western environment, including among the so-called “spiritual practitioners”. This happens for the reason that those who declare themselves sādhakas in the West are subject to the trends of the general environment, where a lot of mass delusions are cultivated. But, if you know deeply the topic of mantras, then the mantra is the Deity, and the guru is a good practitioner. A good practitioner is one who has realised the mantra (i.e. the Divine in himself). Accordingly, the transfer of the mantra, of course, occurs from the guru to the disciple, but essentially it is the Deity itself that “transmits” itself through the guru to the disciple. I propose to think about how important, deep and sacred this process is. Therefore, it is necessary to come to the guru precisely for this kind of process. But of course, this does not happen as simply and primitively as many imagine it to be, the level of devotion and understanding of what it is must be extremely high.