Bhagavad Gita, Chapter 4, Verse 38

Verily there exists nothing in this world purifying like knowledge. In good time, having reached perfection in Yoga, one realises that oneself in one's own heart.

Knowing about this isn't the same as having it. It settles in slowly, through steady practice.

Krishna draws a line between knowing something intellectually and receiving it. That deeper kind of understanding arrives gradually, as the natural result of consistent practice, not as a one-time download.