Shiva Purana
अकारः सर्ववर्णाग्र्यः प्रकाशः परमः शिवः ॥ हकारो व्योमरूपः स्याच्छक्त्यात्मा संप्रकीर्तितः ॥ २ ॥
‘A’ is the foremost among all letters. It is the greatest splendour ‘Śiva’. The letter ‘Ha’ is of the form of firmament. It is glorified as the Śakti-soul.
english translation
akAraH sarvavarNAgryaH prakAzaH paramaH zivaH ॥ hakAro vyomarUpaH syAcchaktyAtmA saMprakIrtitaH ॥ 2 ॥
hk transliteration by Sanscript