SB 10.51.56

tasmād visṛjyāśiṣa īśa sarvato
nirañjanaṁ nirguṇam advayaṁ paraṁ
 tvāṁ jñāpti-mātraṁ puruṣaṁ vrajāmy aham
tasmāt — therefore; visṛjya — putting aside; āśiṣaḥ — desirable objects; īśa — O Lord; sarvataḥ — entirely; rajaḥ — with passion; tamaḥ — ignorance; sattva — and goodness; guṇa — the material modes; anu-bandhanāḥ — entangled; nirañjanam — free from mundane designations; nirguṇam — transcendental to the material modes; advayam — nondual; param — supreme; tvām — You; jñāpti-mātram — pure knowledge; puruṣam — the original person; vrajāmi — am approaching; aham — I.
Therefore, O Lord, having put aside all objects of material desire, which are bound to the modes of passion, ignorance and goodness, I am approaching You, the Supreme Personality of Godhead, for shelter. You are not covered by mundane designations; rather, You are the Supreme Absolute Truth, full in pure knowledge and transcendental to the material modes.

The word nirguṇam here indicates that the Lord’s existence is beyond the qualities of material nature. One might argue that Lord Kṛṣṇa’s body is made of material nature, but here the word advayam refutes that argument. There is no duality in Lord Kṛṣṇa’s existence. His eternal, spiritual body is Kṛṣṇa, and Kṛṣṇa is God.