Shiva Purana
यदि पापस्तु भुंजीत स्वैरं तय्स न निष्कृतिः ॥ प्रमादेन तु भुंक्ते चेत्तदुद्गीर्य प्रयत्नतः ॥ ७० ॥
If a sinner eats it at will, he is not expiated. If he eats it carelessly he should swallow it with great effort.
english translation
yadi pApastu bhuMjIta svairaM taysa na niSkRtiH ॥ pramAdena tu bhuMkte cettadudgIrya prayatnataH ॥ 70 ॥
hk transliteration by Sanscript