The personal form and impersonal form, there are two conception. But Kṛṣṇa explains this that mayā tatam idaṁ sarvaṁ jagad avyakta-mūrtinā (BG 9.4). Avyaktam, impersonal. That is another form of Kṛṣṇa. He says, mayā: "By Me." "I am all-pervading." Mayā tatam idaṁ sarvam. That is sarvaṁ khalv idaṁ brahma. Because He is expanded everywhere, that is impersonal. And... But as māyā, He says, "by Me." Then He's person. So the whole creation is Kṛṣṇa's expansion of energy.
Just like the sunshine. Sunshine is also the same quality, heat and light, as the sun globe or the sun god. But the sunshine is impersonal, and the sun globe is localized. And within the sun globe there is sun god. So that is the main source of everything. Īśvaraḥ paramaḥ kṛṣṇaḥ sac-cid-ānanda-vigrahaḥ (Bs. 5.1). Brahmaṇaḥ ahaṁ pratiṣṭhā. The brahmajyoti is also staying in Kṛṣṇa. Kṛṣṇa is the source of brahmajyoti. So impersonal or personal, whatever you take, that is Brahman. Brahmeti paramātmeti bhagavān iti śabdyate (SB 1.2.11).