Skanda Purana 4.41.235

4.41.235

ākāśaṃ ca marīcivārisadṛśaṃ yadbrahmaraṃdhrasthitaṃ yannāthena sadāśivena sahitaṃ śāṃtaṃ hakārākṣaram ..

And space resembles mirage water, situated in the aperture of Brahmā, accompanied by its master Sadāśiva, tranquil, having the syllable 'ha';