For anything which exists there must be a reason, and for anything which does not exist, then there is a reason why it does not exist. Now Kṛṣṇa's existence, therefore, is most certain, because any reason which could deny Kṛṣṇa's existence is impossible to be found. "Kṛṣṇa" means He is the all-inclusive entity. Therefore any reason which could prevent Kṛṣṇa's existence would have to be either external to His own divine nature or in His own nature. Nothing can be outside of Kṛṣṇa's all-inclusiveness.
Therefore no external agent can prevent Kṛṣṇa's existence. And it is again self-contradictory to attribute any imperfection to the perfect being. Therefore the conclusion is that Kṛṣṇa necessarily exists because no one can prevent His existence. By definition, God is the perfect entity. So just as we've seen that existence of Kṛṣṇa cannot be checked . . . and actually, nobody can prove that Kṛṣṇa does not exist, neither can they prevent Him from existing.