Shiva Purana
महासंशयमापन्नौ प्रकृतिः पुरुषश्च तौ ॥ तदा वाणी समुत्पन्ना निर्गुणात्परमात्मनः ॥ तपश्चैव प्रकर्तव्यं ततस्सृष्टिरनुत्तमा ॥ ७॥
Nature and the soul were in great doubt Then a voice emerged from the transcendental Supreme Soul One should also practice austerities and thereby attain supreme creation.
english translation
mahAsaMzayamApannau prakRtiH puruSazca tau ॥ tadA vANI samutpannA nirguNAtparamAtmanaH ॥ tapazcaiva prakartavyaM tatassRSTiranuttamA ॥ 7॥
hk transliteration by Sanscript