In the worldview of archaic man rainfall and fertility can often be insured through religious endeavor.
Mircea Eliade introduces his work Yoga: Immortality and Freedom by observing that in the post-Vedic period, "four basic and interdependent concepts . . . bring us directly to the core of Indian spirituality." These basic and interdependent concepts are karma, maya, nirvana, and yoga. Given the interrelated character of these basic elements in the post-Vedic period, Eliade contends that a "coherent history of Indian thought could be written starting form any one of [them] and the other three would inevitably have to be discussed."
It is therefore not surprising for Manu to note that even the gods decale the power of tapas to be "incomparable" (11, 245), indeed: "All the bliss of gods and men is declared by the sages to whom the Veda was revealed, to have tapas for its root, tapas for it's middle, and tapas for its end. (11, 235)