Shiva Purana
त्रिकालं शिवपूजां च कुर्वंति स्म निरन्तरम् ॥ नानाविधैः स्तवैर्दिव्यैस्तुष्टुवुस्ते मुनीश्वराः ॥ ७॥
O great sages, they performed the worship of Śiva incessantly thrice a day. They eulogised Śiva with different devotional hymns.
english translation
trikAlaM zivapUjAM ca kurvaMti sma nirantaram ॥ nAnAvidhaiH stavairdivyaistuSTuvuste munIzvarAH ॥ 7॥
hk transliteration by Sanscript