Prahlāda Mahārāja is explaining to his demonic class friends. Five-years-old boy, how he's explaining this Sāṅkhya philosophy? Because he's a devotee and he has heard the whole philosophy from authorities, Nārada Muni. Mūkaṁ karoti vācālaṁ paṅguṁ laṅghayate girim (CC Madhya 17.80). Therefore the spiritual masters' mercy is described, mūkhaṁ karoti vācālam. Mūkham means dumb, one who cannot speak. He becomes a great lecturer or speaker. Although he is dumb, but he can become a great lecturer, mūkhaṁ karoti vācālam.
Paṅguṁ laṅghayate girim: and one who is lame, who cannot walk, he can cross over the mountains. Mūkhaṁ karoti vācālaṁ paṅguṁ laṅghayate . . . yat kṛpā tam ahaṁ vande, that "By whose mercy these things are possible, I offer my respectful obeisances," param ānanda bhavam, "the Supreme Personality of Godhead, reservoir of all pleasure." By Kṛṣṇa's mercy it is possible.
By material calculation it is not possible. Material calculation one will say that, "How it is possible, you say the dumb is lecturing very nicely? That is not possible." Or, or that, "Lame man is now crossing the mountains"? So materially it is not possible. But by the mercy of Kṛṣṇa or His representative . . .
Just like Prahlāda Mahārāja, five-years-old boy, he is explaining so nicely about the constitution of the soul. Why? Because he has obtained the mercy of Nārada Muni, the representative of Kṛṣṇa. So it is possible.