Bhagavad Gita Chapter 3.14
annād bhavanti bhūtāni
parjanyād anna-sambhavaḥ
yajñād bhavati parjanyo
yajñaḥ karma-samudbhavaḥ
Translation
All living bodies subsist on food grains, which are produced from rains. Rains are produced by performance of yajna [sacrifice], and yajna is born of prescribed duties.