Mundaka 1.01

ब्रह्मा देवानां प्रथमः सम्बभूव विश्वस्य कर्ता भुवनस्य गोप्ता। स ब्रह्मविद्यां सर्वविद्याप्रतिष्ठां अथर्वाय ज्येष्ठपुत्राय प्राह ॥१॥

brahmā devānāṃ prathamaḥ sambabhūva viśvasya kartā bhuvanasya goptā। sa brahmavidyāṃ sarvavidyāpratiṣṭhāṃ atharvāya jyeṣṭhaputrāya prāha ॥1॥

[ब्रह्मा (brahmā) - Brahma; देवानाम् (devānām) - of the gods; प्रथमः (prathamaḥ) - first; सम्बभूव (sambabhūva) - was born; विश्वस्य (viśvasya) - of the universe; कर्ता (kartā) - creator; भुवनस्य (bhuvanasya) - of the world; गोप्ता (goptā) - protector; सः (saḥ) - he; ब्रह्मविद्याम् (brahmavidyām) - knowledge of Brahman; सर्वविद्या (sarvavidyā) - of all knowledge; प्रतिष्ठाम् (pratiṣṭhām) - foundation; अथर्वाय (atharvāya) - to Atharva; ज्येष्ठपुत्राय (jyeṣṭhaputrāya) - to the eldest son; प्राह (prāha) - taught;]

Brahma, the first of the gods, was born the creator and protector of the universe. He imparted the supreme knowledge of Brahman, which is the basis of all knowledge, to Atharva, his eldest son.

Bhāshya 1.01

A testimonial from Brahmāṇḍ Purāna explains how Shiva was first son of Lord Brahma in the first kalpa, while Atharva was the firs son in the Vaivasvata Manu kalpa.

मनोर्वैवस्वतस्याऽदावथर्वा ब्रह्मणोऽजनि। मित्रश्च वरुणश्चाथो प्रहेतिर्हेतिरेव च। ब्रह्मणः प्रथमे कल्पे शिवः प्रथमजः सुतः। सनकाद्यास्तु वाराहे ब्रह्मा विष्णोः सुतोऽग्रजः॥

manorvaivasvatasya'dāvatharvā brahmaṇo'jani। mitraśca varuṇaścātho prahetirhetireva ca। brahmaṇaḥ prathame kalpe śivaḥ prathamajaḥ sutaḥ। sanakādyāstu vārāhe brahmā viṣṇoḥ suto'grajaḥ॥

[मनोः (manoḥ) - of Manu; वैवस्वतस्य (vaivasvatasya) - Vaivasvata; आदौ (ādau) - in the beginning; अथर्वा (atharvā) - Atharva; ब्रह्मणः (brahmaṇaḥ) - of Brahma; अजनि (ajani) - was born; मित्रः (mitraḥ) - Mitra; च (ca) - and; वरुणः (varuṇaḥ) - Varuna; च (ca) - and; अथ (atha) - then; प्रहेतिः (prahetiḥ) - Praheti; हेतिः (hetiḥ) - Heti; एव (eva) - indeed; च (ca) - and; ब्रह्मणः (brahmaṇaḥ) - of Brahma; प्रथमे (prathame) - in the first; कल्पे (kalpe) - kalpa; शिवः (śivaḥ) - Shiva; प्रथमजः (prathamajaḥ) - first-born; सुतः (sutaḥ) - son; सनकाद्याः (sanakādyāḥ) - Sanaka and others; तु (tu) - but; वाराहे (vārāhe) - in the Varaha; ब्रह्मा (brahmā) - Brahma; विष्णोः (viṣṇoḥ) - of Vishnu; सुतः (sutaḥ) - son; अग्रजः (agrajaḥ) - elder; ॥ (॥) - ;]

An the beginning of the reign of Vaivasvata Manu, Atharva was born from Brahma. Subsequently came Mitra and Varuna, followed by Praheti and Heti. In the first kalpa, Shiva was the firstborn son of Brahma. However, during the Varaha kalpa, Sanaka and others are considered firstborn sons, Brahma being the son of Lord Vishnu.

इति ब्रह्माण्डे।

iti brahmāṇḍe।

[इति (iti) - thus; ब्रह्माण्डे (brahmāṇḍe) - in the Brahmāṇḍ Purāna;]

- stated thus in the Brahmāṇḍ Purāna.