Shiva Purana
॥ श्रीदेव्युवाच ॥ उपदिष्टास्त्वया देव मंत्रास्सप्रणवा मताः ॥ तत्रादौ श्रोतुमिच्छामि प्रणवार्थं विनिश्चितम् ॥ २३॥
The goddess said:— O lord, you have discoursed on the Mantras including the Praṇava. There at the outset I wish to know the meaning of the Praṇava.
english translation
॥ zrIdevyuvAca ॥ upadiSTAstvayA deva maMtrAssapraNavA matAH ॥ tatrAdau zrotumicchAmi praNavArthaM vinizcitam ॥ 23॥
hk transliteration by Sanscript