Shiva Purana
अथाम्बरीषस्स नृपः प्रणनाम च तं मुनिम् ॥ शिवावतारं संज्ञाय स्वपरीक्षार्थमागतम् ॥ ४९॥
Then king Ambarisha bowed down to the sage Recognizing him as an incarnation of Lord Śiva he came to test himself.
english translation
athAmbarISassa nRpaH praNanAma ca taM munim ॥ zivAvatAraM saMjJAya svaparIkSArthamAgatam ॥ 49॥
hk transliteration by Sanscript