Ramayana
स्वयम्भूरजितो देवो यन्नापश्यन्सुरासुराः । अदृश्यः सर्वभूतानां तेनायं तु शरोत्तमः ॥ 7-63-21 ॥
"that unconquered, self-born god, whom neither gods nor demons could behold, who is unseen by all beings; and therefore this is the most excellent of arrows."
english translation