Rāja-vidyā raja . . . very confidential. If you want to get this knowledge, then you have to take to Kṛṣṇa consciousness. Otherwise, it is not possible. Just like a dog cannot get university education. That is not possible. He must get a human body. It is not possible, but anyone can understand a little, that this rāja-vidyā rāja-guhyaṁ, this knowledge, this spiritual knowledge, Kṛṣṇa knowledge, is most confidential and the king of all knowledge. Pavitram. Pavitram means "Not contaminated." Here in this material world everything is contaminated by the material qualities: sattva-guṇa, rajo-guṇa, tamo-guṇa, goodness, passion and ignorance.
But this knowledge, Kṛṣṇa knowledge, is transcendental. It is not contaminated. Therefore uttamam. Uttamam. Every word has got meaning. Pavitram idam uttamam. Ut, ut means "transcendental," "above." And tama, tama means "darkness." This world is dark. Every one of you know that it is, by nature, it is dark. Therefore, here we require sunlight, moonlight, electricity. Just like if you live in a dark room, you must always have light, electricity. Otherwise you are blind.
So this material world, whole universe, they are brightened by the sunshine. Kṛṣṇa is so kind. Because you cannot see without sunshine, without light—this place is dark—therefore in daytime there is sunshine; at night there is moonshine. Everything is arranged there.