Kalahastishavilasa 1.78

1.78

rudrasya ca brahma lalāṭotpattervaradāna prayuktatvena
prādurbhāvarūpatvāt | lalāṭādrudro'jāyata iti svatantrotpatti
pratītivat | atharvabhāratavākyayoḥ svatantrotpatti
śravaṇābhāvāt | pratyuta sṛjyatvena pāratantryapratīteḥ nāma
me kurviti rudrājñā purassarameva nāmākaroditi
caturmukhenanāmakaraṇācca | tasya ca kālāgnirudratvena
paramakāraṇātparameśvarādbhinnatva pratipādanāt |
ityabhidhyāyato nāsāvivarātsahasānaghā varāhatopi
naragādaṅguṣṭhaparimāṇataḥ || iti bhāgavata vacanena
caturmukhasya nāsikāyā nārāyaṇotpattiśravaṇāt | vāmanapurāṇe
ca -

And since Rudra's origination from Brahmā's forehead was occasioned by the granting of a boon, it was in the nature of an appearance; just as it is recognized as an independent origination in the statement, 'Rudra was born from the forehead.' Because in the texts of the Atharvaveda and the Mahābhārata no independent origination is heard; on the contrary, dependence is recognized through [his] being created, and because four-faced Brahmā performed the naming solely preceded by Rudra's command, 'Make a name for me!' And because, through his being Kālāgnirudra, he is established as distinct from the Supreme Lord, who is the ultimate cause. By the statement of the Bhāgavata: 'As he was thus meditating, suddenly, O sinless one, a boar of the size of a thumb came out from the cavity of his nose,' since Nārāyaṇa's origination from four-faced Brahmā's nose is heard; and in the Vāmanapurāṇa: