Tafsir of Ghafir 40:50

(They will say, "Did your messengers not come to you with clear proofs?") That is: Were you not alerted to this? And did your messengers not come to you in the world, continuously, with clear arguments indicating the evil consequences of the disbelief and disobedience you were upon? This is as in the saying of the Exalted: "Did there not come to you messengers from among yourselves, reciting to you the verses of your Lord and warning you of the meeting of this Day of yours?" By this, they intend to bind them [to their own admission] and rebuke them for [their] waste of the times of supplication and [their] abandonment of the causes for [its] acceptance.

(They will say, "Yes") That is: They came to us with them, but we denied them, just as the words of the Exalted clearly state: "Yes, a warner had come to us, but we denied and said, 'Allah has not sent down anything. You are not but in great error.'"

The fa (the 'so') in the saying of the Exalted: (They will say, "Then call...") is fasihah (elliptical/eloquent), meaning: Since the matter is as such, then you call out [yourselves], for supplication from those who do what you did is impossible to proceed from us. It is said, in explaining the refusal of the keepers [of Hell] to supplicate: "For we have not been permitted to supplicate for the likes of you." This is critiqued in that—aside from being devoid of explaining that the cause lies with the disbelievers, which the fa clarifies—it might imply that permission is within the realm of possibility, and that if they were permitted, they would do so. Therefore, the first explanation is more appropriate.

They did not intend by their command to "call" to make them hopeful of an answer, but rather to make them despair of it and to manifest their disappointment, as they explicitly stated in their words: (And the supplication of the disbelievers is not but in error.)

(That is, in loss and falsehood; meaning it is not answered.) This sentence is from the speech of the keepers. It is also said: It is from the speech of the Exalted, informing His Messenger Muhammad (peace and blessings be upon him) of it. It has been used as an absolute proof by those who say that the supplication of a disbeliever is never answered and that he is not to be permitted to go out for Istisqa (prayer for rain).

The truth is that the verse concerns the supplication of the disbelievers on the Day of Resurrection, and that a disbeliever might experience in this world that which he calls upon and requests from Allah, as a result of his supplication, to which many verses testify. As for whether or not this is to be called "acceptance," it is a discussion of no benefit.

And the saying of the Exalted: [continues]