Shiva Purana
न भिषक्कारणं रोगे शिवः संसारकारणम् ॥ इत्येतदपि वैषम्यं न दोषायास्य कल्पते ॥ ८६ ॥
This inequality like the physician is not the cause of the ailment. So Śiva is the cause of worldly existence need not be a symbol of defect.
english translation
na bhiSakkAraNaM roge zivaH saMsArakAraNam ॥ ityetadapi vaiSamyaM na doSAyAsya kalpate ॥ 86 ॥
hk transliteration by Sanscript