The mystery of religious life is very, very secret. Secret means for ordinary man it is very difficult to understand. Therefore śāstra says tarko 'pratiṣṭhāḥ. If you want to learn what is spiritual life simply by your argument, dry, philosophical speculation, it will never be achieved. Tarko 'pratiṣṭhāḥ śrutayo vibhinnā. If you study the Vedas, there are different Vedas. Principally Sāma, Yajur, Atharva, Ṛg. But you cannot understand the objective of the Vedas simply by studying yourself. Therefore Vedas says, Kaṭhopaniṣad, tad vijñānārthaṁ sa gurum evābhigacchet śrotriyaṁ brahma-niṣṭham samit-pāṇiḥ (MU 1.2.12). Like that. In every śāstra the injunction is if you want to understand the essence of Veda, then you must approach a realized, self-realized person. In the Bhagavad-gītā also the same thing is said. Tad viddhi praṇipātena paripraśnena sevayā (BG 4.34).
So Prahlāda Mahārāja, although he was born of a father who was atheist number one, godless, by the grace of Nārada Muni he became a great devotee. So his father was very careful that nobody comes and instructs his son about Vedic way of lfe or God consciousness, Kṛṣṇa consciousness. He was very careful not to allow anyone. He appointed teachers for his son, strictly prohibiting about... Just like nowadays it has become, what is called? Secular state. Don't talk of God. This is the present situation of the world, atheist class. Don't talk of God. But they do not know that they have not much improved by don't talk of God. The situation is becoming grimmer and grimmer. But they have no eyes to see. They have no eyes to see. This Godless civilization will not make them happy. That's a fact. Harāv abhaktasya kuto mahad guṇa manorathena asato dhāvato bahiḥ (SB 5.18.12). If one is Godless, then however qualified he may be from the material point of view, he is useless. Harāv abhaktasya kuto mahad guṇā. He cannot have any good quality. Why? Manorathena asato dhāvato bahiḥ. Because he is on the mental platform. So by speculation on the mental platform, he will accept which is not spiritual.