Shiva Purana
ईश्वर उवाच ॥ शिवो महेश्वरश्चैव रुद्रो विष्णुः पितामहः ॥ संसारवैद्यस्सर्वज्ञः परमात्मेति मुख्यतः ॥ १ ॥
Lord Śiva said:— Shiva, Maheshwara, Rudra and Vishnu are the grandfathers. The physician of the world is omniscient and chiefly the Supreme Self.
english translation
Izvara uvAca ॥ zivo mahezvarazcaiva rudro viSNuH pitAmahaH ॥ saMsAravaidyassarvajJaH paramAtmeti mukhyataH ॥ 1 ॥
hk transliteration by Sanscript