Shiva Purana
इति प्रोक्तस्तु ते तात ब्रह्मचारि स्वरूपकः ॥ शिवावतारो हि मया शिवाभावपरीक्षकः ॥ ६४ ॥
My dear son, when I had thus spoken to you, I was a celibate and a self-realized being. . I have incarnated Lord Śiva as a test of the absence of Lord Śiva.
english translation
iti proktastu te tAta brahmacAri svarUpakaH ॥ zivAvatAro hi mayA zivAbhAvaparIkSakaH ॥ 64 ॥
hk transliteration by Sanscript