Transliteration
tad viddhi praṇipātena paripraśnena sevayā |
upadekṣayanti te jñānaṃ jñāninas-tattva-darśinaḥ || 34 ||
Translation
Try to learn the truth by approaching a spiritual master. Inquire from him submissively and render service unto him. The self-realized soul can impart knowledge unto you because he has seen the truth.
Purport
In earlier Shlokas, Bhagvan Shri Krishna explained all Yajnas and their relevance. In this Shloka Bhagvan Shri Krishna explains that one of the most authentic ways to know the truth about the Dharma is to approach a true spiritual master(True Guru). This is because a spiritual master might have put many years to realize the truth. Bhagvan Shri Krishna also made it clear that such spiritual must be won by true humble service to him. Knowing the true intentions and purity of pupil the Guru will transfer his knowledge to Pupil.
It is possible to acquire truth by other means, but approaching spiritual master makes the process easy. But one must approach true Guru only and be aware of false Gurus.