Mundaka 1.01
ब्रह्मा देवानां प्रथमः सम्बभूव विश्वस्य कर्ता भुवनस्य गोप्ता। स ब्रह्मविद्यां सर्वविद्याप्रतिष्ठां अथर्वाय ज्येष्ठपुत्राय प्राह ॥१॥
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॥
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।
- stated thus in the Brahmāṇḍ Purāna.
