Who requires a guru? It is not a fashion, that one has to accept anyone as guru. No. A person requires a guru when he is inquisitive, tasmād guruṁ prapadyeta jijñāsuḥ, when he is very much eager to understand the spiritual, śreya uttamam. Uttamam. Ut means transcendental, and tama means darkness. This world is called darkness, ignorance. So one who wants to transcend this position of ignorance and wants to know the transcendental subject, means spiritual subject, brahma-jijñāsā, he requires a guru, not any person, other person.
-Lecture Chaitanya Charitamrit Madhya Chapter 20 Verse 101-104 - Bombay

अच्छेद्योऽयमदाह्योऽयमक्ल‍ेद्योऽशोष्य एव च ।
नित्यः सर्वगतः स्थाणुरचलोऽयं सनातनः ॥ २४ ॥
This individual soul is unbreakable and insoluble, and can be neither burned nor dried. He is everlasting, present everywhere, unchangeable, immovable and eternally the same.
-BG 2.24