Srimad-Bhagavatam: Canto 9 - Chapter 1 - Verse 32
Sanskrit:
तदिदं भगवानाह प्रियाया: प्रियकाम्यया ।स्थानं य: प्रविशेदेतत् स वै योषिद् भवेदिति ॥ ३२ ॥
ITRANS:
tad idaṁ bhagavān āhapriyāyāḥ priya-kāmyayāsthānaṁ yaḥ praviśed etatsa vai yoṣid bhaved iti
Translation:
Thereupon, just to please his wife, Lord Śiva said, “Any male entering this place shall immediately become a female!”