Valmiki Ramayana Ayodhya Kanda Sarga 64 Shloka 25

तपसि observing austerities, तिष्ठति staying, मुनौ at the ascetic, तादृशे similar, ब्रह्मवादिनि at one who propagates selfknowledge, ज्ञानात् knowingly, शस्त्रम् weapon, विसृजतः discharges, मूर्धा head, सप्तधा into seven pieces, फलेत् will break.

'If any one deliberately discharges a weapon upon an ascetic observing austerities or on him who expounds the Vedas, his head will split into seven pieces.