By eating grains we subsist. Our life prolongs by eating grains. So annād bhavanti bhūtāni parjanyād anna-sambhavaḥ. And grains are produced by proper rainfall. Rainfall is the main source of producing everything of our necessities of life. Without rainfall we cannot produce anything of the necessities of life.
We have got many necessities of life, not only grains. We require cotton for clothing. We require silk for luxury. We require valuable stones and jewels. All these are produced under certain circumstances of rain. Rain is falling on the sea and the ocean also. So there is purpose. Under certain constellation of the star, if the rain falls on the sea, it produces pearls and jewels. We have got this information from Vedic literature. So everything is produced, whatever you require.
Now, pasturing ground for the cows—the grass is produced by rains, and the animals, they eat the grass and they produce milk. You require milk. So everything, the main source of supply is the rainfall from the sky. That is not under your control. So Bhagavad-gītā says, parjanyād anna-sambhavaḥ. Without rain, you cannot have any production. Nothing can be produced without rain.
And without production, you cannot live. But rain, regular rain and regulative rain and useful rain, will fall when you perform sacrifices, yajña. Yajñād bhavati parjanyaḥ (BG 3.14). And yajñaḥ karma-samudbhavaḥ: and you can perform yajña by working. Because yajña requires materials, so if you have no money, if you don't work, you cannot have money. So everything is a circle. It is nice circle.