And yet, We had established them securely in a manner in which We have never established you, people of later times;]29
and We had endowed them with hearing, and sight, and [knowledgeable] hearts:30
but neither their hearing, nor their sight, nor their hearts were of the least avail to them, seeing that they went on rejecting God's messages; and [in the end] they were overwhelmed31
by the very thing which they had been wont to deride.
This relates in the first instance to the pagan contemporaries of the Prophet, but applies to later generations as well. - The tribe of 'Ad were the unchallenged lords in the vast region in which they lived (cf. 89:8 - "the like of whom has never been reared in all the land"). Moreover, the social conditions of their time were so simple and so free of the many uncertainties and dangers which beset people of higher civilizations that they could be regarded as more "securely established" on earth than people of later, more complex times.
I.e., intellect and feeling, both of which are comprised in the noun fu'ad.