Skandapurana 16.200.7

16.200.7

.. brahmovāca .. ..
avadhyaḥ sa tu sarveṣāṃ devānāmiti me matiḥ ..
ṛte tu śāṃkaraṃ tejo nānyena vinipātyate ..
tasmādgacchata bhadraṃ vo devadevaṃ maheśvaram .. 7 ..

Brahmā said: / 'He cannot be slain by all the gods; this is my opinion. / Except for the splendor of Śaṃkara, he cannot be brought down by any other. / Therefore, go—may good betide you—to Maheśvara, the god of gods.