Shiva Purana
यथा निकृष्टानुत्कृष्टान्सर्वानप्यात्मनः शिवः ॥ क्षमते रक्षितुं तद्वन्मंत्रो ऽयमपि सर्वदा ॥ ४४ ॥
Just as Śiva, this mantra too is capable of protecting all Atmans base or excellent.
english translation
yathA nikRSTAnutkRSTAnsarvAnapyAtmanaH zivaH ॥ kSamate rakSituM tadvanmaMtro 'yamapi sarvadA ॥ 44 ॥
hk transliteration by Sanscript