The Soul is awareness. In order for the mind to merge with the Soul it must become like it. Therefore, the thinking mind must cease and become the meditative mind which is singular in thought. A singular thought is awareness.
The subconscious mind is always aware and always in the present moment. The conscious mind can either stay within it and become the meditative mind or it can rise out of it and become the thinking mind.
The subconscious mind is often referred to as the heart as it holds the emotional body within it.
Therefore, be still in the heart and know that I AM
~ Tracy Pierce