There is fear from duality. (Non-duality alone is fearless). (Chapter 1. 4.2).
Yajnavalkya said: O Janaka! You have attained the fearless (Brahman). (Chapter 4. 2..4).
Brahman is fearless; one who knows this, becomes the fearless Brahman. The knower of the fearless Brahman becomes himself absolutely fearless. (Chapter 4.4. 25).
(Source: Conquest of Fear by Swami Sivananda)