Just like Mahārāja Parīkṣit, while he was touring on his kingdom, he saw that one man was trying to kill a cow. Parīkṣit Mahārāja saw. Immediately he took his sword that, "Who are you? You are killing a cow in my kingdom?" Because the king is supposed, or the government is supposed to give everyone protection. Not that the government is meant for giving protection to the human being, not to the animals. Because it is Kali-yuga, the government discriminates between two nationals. National means one who has taken birth in the land. That is called national. That is . . . you know, everyone.
So the trees, they are also born in the land, the aquatics also born in the land. The flies, the reptiles, the snakes, the birds, the beasts, human being—everyone is born in that land. Suppose your land, America, United States, why the government should give protection to one class of living entities, rejecting others? This means they have lost their sympathy for others. This is Kali-yuga. Formerly, before Kali-yuga, unnecessarily even an ant would not be killed. Even an ant. There are many instances that a hunter who was taking advantage of killing animals, but when he became a devotee he was not prepared to kill even an ant.
So the Kṛṣṇa consciousness movement is so nice that it makes a person perfect in everything: perfect in knowledge, perfect in strength, perfect in age—everything. We need so many things. So this perfection of life, the process how to make life perfect, is coming down from Kṛṣṇa. Kṛṣṇa, He is the origin of everything. Therefore the knowledge of perfection is also coming from Him, and periodically—periodically means after millions and millions of years—Kṛṣṇa comes. He comes once in a day of Brahmā.
So Brahmā's days, even one day, the span of one day, it is very difficult to calculate. Sahasra-yuga-paryantam arhad yad brāhmaṇo viduḥ (BG 8.17). The Brahmā's one day means about 433,000,000's of years. So in each day of Brahmā, Kṛṣṇa comes, once in a day. That means after a period of 433,000,000's of years He comes. Why? To give perfect knowledge of life, how a human being should live to make his life perfect. So the Bhagavad-gītā is there, spoken by Kṛṣṇa in this millennium, in this day. Now Brahmā's one day we are passing through the twenty-eighth millennium. No, twenty-eighth . . . in Brahmā's day there are seventy-one Manus, and one Manu lives for . . . that is also many millions of years, seventy-two millenniums.