The Lord is the Supersoul seated in everyone’s heart, and He acts as the caitya-guru, the spiritual master within. However, He gives direct instructions only to the advanced, pure devotees. In the beginning, when a devotee is serious and sincere, the Lord gives him directions from within to approach a bona fide spiritual master. When one is trained by the spiritual master according to the regulative principles of devotional service and is situated on the platform of spontaneous attachment for the Lord (raga-bhakti), the Lord also gives instructions from within.

From Srila Prabhupada’s purport to Srimad Bhagavatam 4.28.41