Valmiki Ramayana 7.85.7

एकांशो वासवं यातु द्वितीयो वज्रमेव तु ।तृतीयो भूतलं शक्रस्तदा वृत्रं वधिष्यति॥

ekāṃśo vāsavaṃ yātu dvitīyo vajrameva tu |tṛtīyo bhūtalaṃ śakrastadā vṛtraṃ vadhiṣyati ||

Our plain-language meaning of this verse is waiting for scholar review.