To change the deepest subconscious a seed, or bij, is needed. The ideal seed is a mantra. The mantra is not just any sound or thought. In a sense, mantras pre-exist as the DNA of God. They are in each cell of the creation. Their sound has focus, and contains a provocative seed which provides a template for higher experience. Repeating a mantra restructures the patterns in the mind that filter experience.
Yogi Bhajan describes the process this way: When you meditate deeply into an ecstatic self-hypnosis that joins together heavens, earth and self, the subconscious releases a flood of thoughts, wave after wave. Every thought has impact and results. To break old patterns, you must take the support of a thunderbolt—a mantra to cut to the core of your negative thoughts and turn their energy to positive.
When you merge into anahat (when the mantra resounds in every cell) through the use of mantra and rhythm, you vibrate a seed, a template of Infinity, that resides in the center of every cell and atom of you like spiritual DNA. When every part of you vibrates, we call that state Ang Sung Wahe Guru. Ang means a part of you. Wahe Guru is a state of ecstasy. Sung means every. So every part of you vibrates as one in a merger in ecstasy of consciousness. You become the mantra and the entire Universe meditates on you.
Excerpt from the KRI Aquarian Teacher Training Manual Level 1 p. 133