While explaining about Yagnas according to the Vedas, I have heard from elders that the Devata is bound by mantra (Devadhinam jagat Sarve mantraadhinam cha Devataa).
However, in an article on his website, Devdutt Patnaik says the following :
Yagna is not a contract. In a contract, there is give and take; there is obligation. Yagna is give in order to get. It is entirely voluntary. The devata has no obligation.
Which scripture is he quoting or referring to ?