Yoga Sūtra Chapter Two verse 9

स्वरस्वाहि विदुषोऽपि समारूढोऽभिनिवेशः ॥९॥

sva-rasa-vāhī viduṣaḥ api samā-ruḍhaḥ abhiniveśaḥ ||9||

The will to stay alive is a continuous self-disposition;
constantly springing up, even in the wise person.

sva - ownrasa - dispositionvāhī - continuousvidvāṃs - wise personapi - alsosamā - equal, constantruḍha - springing upabhiniveśa - tenacity; the will to stay alive; fear of death;

Commentaries and Reflections

T Krishnamacharya:

Abhiniveśā is the extra-ordinairy instinctive urge to survive at any cost.
No one is spared.
In a way it is a dislike about one’s death.

There are essentially three causes for fear….
desire, disease and death.