It is prescribed in śāstra, and it is said, kṛte yad dhyāyato viṣṇum. Kṛte means in the Satya-yuga or what is generally known as golden age. So in the Satya-yuga people used to realize self or used to elevate themselves to highest perfection of life by meditation. Meditation. You have heard the name of Vālmīki Muni. Vālmīki Muni, he meditated for sixty thousands of years. His whole body was covered by, what is called, worms. And... Because at that time people used to live for one hundred thousands of years. So gradually our life is being reduced. Yes. In the Satya-yuga, it is stated, that people used to live for one hundred thousands of years. And then, in the Tretā-yuga, they used to live for one thousands of years. No. In the Dvāpara-yuga for one thousand. And in the Tretā-yuga, ten thousand years. In the Dvāpara-yuga one thousand years. And now it has come down to one hundred years in this Kali-yuga. That also, one hundred years is not completed. Now we are dying within sixty or seventy and gradually it will be reduced to twenty to thirty years. That is also mentioned.
So what was possible in the Satya-yuga by meditation, that is not possible in this age. That is not possible. Therefore the methods have been made easier. Kṛte yad dhyāyato viṣṇum. What was being possible, to attain perfection of life by meditation in the Satya-yuga, that was possible in the Tretā-yuga by offering of big sacrifices. Kṛte yad dhyāyato viṣṇuṁ tretāyāṁ yajato makhaiḥ. Makhaiḥ means big sacrifices.