BṚHADĀRAṆYAKA UPANISHAD · 4.4.25

स वा एष महान् अज आत्माजरो ऽमरो ऽमृतो ऽभयो ब्रह्म ।
अभयं वै ब्रह्म ।
अभयं हि वै ब्रह्म भवति य एवं वेद ॥

sa vā eṣa mahān aja ātmājaro ’maro ’mṛto ’bhayo brahma ।
abhayaṃ vai brahma ।
abhayaṃ hi vai brahma bhavati ya evaṃ veda ॥

This great, unborn Self, undecaying, undying, immortal, fearless, is indeed Brahman. Fearless is Brahman, and he who knows this becomes verily the fearless Brahman.