Bhagavatapurana 1.10.19

1.10.19

aśrūyantāśiṣaḥ satyāstatra tatra dvijeritāḥ /
nānurūpānurūpāśca nirguṇasya guṇātmanaḥ //

19. Everywhere were heard benedictions of real force chanted by Brahmins—benedictions which do not become Him as Nirguna (as the Supreme Being), but do so only when He manifests Himself as a Gunatma (a conditioned being.)