After reading Bhagavad-gītā, they are accusing Kṛṣṇa as immoral. One professor in Oxford University, he is a student or professor of Bhagavad-gītā, has written book. Now his conclusion is that Kṛṣṇa is immoral. That means he could not understand Bhagavad-gītā. Bhagavad-gītā cannot be understood by any demon or third-class man. That is explained in the Bhagavad-gītā. Kṛṣṇa said to Arjuna that: "I am speaking to you the same Bhagavad-gītā (BG 4.1), science of God, which I spoke millions of years ago to the sun-god, because the paramparā is lost and I have picked up you because bhakto 'si me priyo 'si (BG 4.3), you are very dear friend and bhakta."
So Bhagavad-gītā is not meant for the demons or the abhaktas. The first condition is that he must be a devotee of Kṛṣṇa. Then it will be revealed. Otherwise it is not possible. Nāhaṁ prakāśaḥ sarvasya yoga-māyā-samāvṛitaḥ (BG 7.25). Na māṁ duṣkṛtino mūḍhā prapadyante narādhamāḥ (BG 7.15). These things are there. So if one is devotee of Kṛṣṇa, he can understand Bhagavad-gītā very easily. Just like Arjuna understood within half an hour. Others, they cannot understand.