Shiva Purana
शिवनिन्दा गुरोर्निन्दा शिवज्ञानस्य दूषणम् ॥ देवद्रव्यापहरणं द्विजद्रव्यविनाशनम् ॥ ९ ॥
Blasphemy against Lord Śiva is blasphemy against the spiritual master and it is a corruption of knowledge of Lord Śiva stealing the property of gods and destroying the property of brahmins.
english translation
zivanindA gurornindA zivajJAnasya dUSaNam ॥ devadravyApaharaNaM dvijadravyavinAzanam ॥ 9 ॥
hk transliteration by Sanscript