Shiva Purana
कृष्णोपदेशतश्शम्भोस्तपः कृत्वातिदारुणम् ॥ प्राप्य चास्त्रं शम्भुवराज्जिग्ये तानर्जुनस्ततः ॥ १८॥
At the instance of Kṛṣṇa, Arjuna, performed the severe penance of Śiva and obtained a divne missile duo to Śiva’s boon. He then conquered the Kauravas.
english translation
kRSNopadezatazzambhostapaH kRtvAtidAruNam ॥ prApya cAstraM zambhuvarAjjigye tAnarjunastataH ॥ 18॥
hk transliteration by Sanscript