The Srimad-Bhagavatam explains that Krishna helps us surrender to Him from within the heart as caitya-guru. Caitya-guru means the Lord in the heart. However, before we are able to perceive the Lord’s dictations, we must purify our existence. To purify our existence, we must accept some discipline by which our hearts can become cleansed. Lord Brahma is an example of this. He was the first created being within the universe, and he had no one he could accept as spiritual master except Krishna. Lord Brahma wanted to understand his origin. Therefore, he voluntarily accepted the discipline the Lord Himself prescribed. When Lord Brahma entered the Garbhodaka Ocean through the stem of the lotus, he heard the syllables “tapa”. Brahma accepted that these syllables were of divine origin, so he agreed to follow them and underwent great austerities for a thousand celestial years by sitting on his lotus seat in meditation. The result of Brahma’s obedient austerity was that the Lord personally revealed Himself to him and showed him the expanse of the Vaikuntha planets.
(Lecture SB 1.8.29 St.Peterburg)