CC Madhya 22.7
‘svarūpa-śakti’ rūpe tāṅra haya avasthāna
“Kṛṣṇa is the nondual Absolute Truth, the Supreme Personality of Godhead. Although He is one, He maintains different personal expansions and energies for His pastimes.
The Lord has many potencies, and He is nondifferent from all these potencies. Because the potencies and the potent cannot be separated, they are identical. Kṛṣṇa is described as the source of all potencies, and He is also identified with the external potency, the material energy. Kṛṣṇa also has internal potencies, or spiritual potencies, which are always engaged in His personal service. His internal potency is different from His external potency. Kṛṣṇa’s internal potency and Kṛṣṇa Himself, who is the potent, are always identical.