Shiva Purana
तस्मादीशप्रसादार्थं यूयं गत्वा भुवं द्विजाः । दीर्घसत्रं समाकृध्वं यूयं वर्षसहस्रकम् १५ ।
Hence, O Brahmins, all of you descend to the earth, to propitiate the Lord. You have to perform a sacrifice of long duration for a thousand years.
english translation
tasmAdIzaprasAdArthaM yUyaM gatvA bhuvaM dvijAH । dIrghasatraM samAkRdhvaM yUyaM varSasahasrakam 15 ।
hk transliteration by Sanscript