Mahabharata 7.57.16

पार्थ पाशुपतं नाम परमास्त्रं सनातनम्येन सर्वान्मृधे दैत्याञ्जघ्ने देवो महेश्वरः

pārtha pāśupataṃ nāma paramāstraṃ sanātanamyena sarvānmṛdhe daityāñjaghne devo maheśvaraḥ

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