atma me darsito ’bahih
nalena salile mulam
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
When you were contemplating whether there was a source to the stem of the lotus of your birth and you even entered into that stem, you could not trace out anything. But at that time I manifested My form from within.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The Personality of Godhead can be experienced only by His causeless mercy, not by mental speculation or with the help of the material senses. Material senses cannot approach the transcendental understanding of the Supreme Personality of Godhead. He can be appreciated only by submissive devotional service when He reveals Himself before the devotee. Only by love of Godhead can one know God, and not otherwise. The Personality of Godhead cannot be seen with the material eyes, but He can be seen from within by spiritual eyes opened by the ointment of love of Godhead. As long as one’s spiritual eyes are closed due to the dirty covering of matter, one cannot see the Lord. But when the dirt is removed by the process of devotional service, one can see the Lord, without a doubt. Brahma’s personal endeavor to see the root of the lotus pipe failed, but when the Lord was satisfied by his penance and devotion, He revealed Himself from within with no external endeavor.