Listening, listening whole day, Completion whole night, is the life of a Yogi. Listening whole day, Completion whole night, means being in the space of listening throughout the day, being in the space of Completion throughout the night.
Listening is Dhyana, Completion is Samadhi.
When you listen in the source of the words and thoughts, which is the neck, which is the throat, you will be in the space of Unclutching, even poison will not cross this and grow and disturb your body. That is what is the meaning of “Neelakanta”; because Mahadeva is established in the pure space of listening, even poison cannot cross his listening, the power of listening, and affect his body.