“Generations before you have passed away; so travel through the land and observe how the deniers fared.”

This is a vast subject. For that reason Allah has invited His creatures to reflect with intellect grounded in sensory evidence, and He has shown that such reflection agrees with what the messengers have conveyed through revelation. He, Exalted is He, says:

“We shall show them Our signs on the horizons and within themselves until it becomes clear to them that it is the truth. Is it not sufficient that your Lord is, over all things, a Witness?”

He thus informs us that He will let people behold outward and inward signs proving the Qur’an to be the truth, so that soundly transmitted revelation and what reason perceives through the senses are in full harmony.

Allah the Most High also says:

“Have they not traveled through the land so that they might have hearts with which to reason, or ears with which to listen? For surely it is not the eyes that grow blind, but the hearts within the breasts that grow blind.”

And He says:

“How many a generation We destroyed before them—people mightier in prowess than they—who scoured the lands; yet was there any place of escape? Surely in that is a reminder for whoever possesses a heart, or lends an ear while he is attentive.”

Concerning the inhabitants of the Fire He says:

“They will say, ‘If only we had listened or used our reason, we would not have been among the companions of the Blaze.’”

And He says:

“We have certainly created for Hell many of the jinn and humankind: they have hearts with which they do not understand, eyes with which they do not see, and ears with which they do not hear….”