Verse 32

अभ्यस्ता बहवस्तेन मिथः प्रेरितपर्वताः ।भीमाः समरसंरम्भाः सममस्मत्पितामहः

In plain words

Many were the terrible fevers of battle, mountains hurled against one another, that he fought, time and again, with our own grandfather.