The title is self-contradictory, because a guru by definition will not contradict śāstra. But in the modern age, anything is possible, because both gurus and modern sādhakas, riding the waves of emotionality, get sucked up into inauthentic paths. A guru’s qualification is not explained anywhere in the śāstra to be the number of their followers, nor to be their eloquence or charisma. It is their rigorous training and faith in śāstra which is the main qualification of a guru. Later when a (rare) sādhaka comes to his or her senses, they may face the horrific prospect of following their guru and contradicting śāstra, or giving up their guru and following śāstra. In either case, the sādhaka creates an offense. So the question is, which is the bigger offense?
In the Bhakti Sandarbha, Sri Jiva Goswami examines the sixth offense: hari-nāmni kalpanam, “to ascribe one’s own imaginary meaning to the name.” In this context, he cites a verse from the Vyāsa-Gītā from Kurma Purāṇa:
deva-drohād guru-drohaḥ koṭi-koṭi-guṇādhikaḥ
jñānāpavādo nāstikyaṁ tasmāt koṭi-guṇādhikam
Hostility toward one’s guru is millions upon millions of times worse than hostility toward the deity. To contradict the authorized conclusions of scripture (jñāna-apavāda) is atheism (nāstikyam), and to do so is millions of times worse than hostility toward one’s guru. (KP 2.16.18)
The giving up of one’s guru is considered a severe offense on the path of bhakti. But if one is faced with the difficult choice of giving up guru or knowingly contradicting śāstra, the choice is clear- one must give up the guru. A guru is subordinate to śāstra; indeed, the guru’s authority derives from śāstra. This shows that, a genuine guru, would never contradict śāstra, and a guru who contradicts śāstra is not qualified to be a guru. It follows then, that leaving a guru because of their distortion of śāstra, is in fact not at all an offense.
In this regard, defending and preserving śāstra from distortions is an important service to one’s tradition. To quote Śrī Babaji:
“It is an important service to the ācāryas to refute misconceptions that are passed off as their own teachings when in fact they contradict them.”