CC Madhya 20.354
muni saba jāni’ kare lakṣaṇa-vicāra
“An actual incarnation of God never says ‘I am God’ or ‘I am an incarnation of God.’ The great sage Vyāsadeva, knowing all, has already recorded the characteristics of the avatāras in the śāstras.
In this verse it is clearly stated that a real incarnation of God never claims to be a real incarnation. According to the symptoms described in the śāstra, one can understand who is an avatāra and who is not.