Shiva Purana
ततो महेश्वरं साक्षान्मूर्तिष्वपि सदाशिवम् ॥ क्रियासु निष्क्रियस्यापि शिवस्य परमात्मनः ॥ १८ ॥
Then Lord Maheśvara appeared directly in all His forms, even Lord Śiva. Even though he is inactive in his actions, Lord Shiva is the Supreme Soul.
english translation
tato mahezvaraM sAkSAnmUrtiSvapi sadAzivam ॥ kriyAsu niSkriyasyApi zivasya paramAtmanaH ॥ 18 ॥
hk transliteration by Sanscript