acquire on its own. Indeed, whoever loses one of these organs thereby loses the knowledge for which it served as the means. A deaf person does not know the knowledge conveyed in speech, and a blind person does not perceive the profound wisdom embodied in visible forms. Likewise, whoever looks at things without engaging his heart, or listens to the words of people of knowledge without engaging his heart, understands nothing. Everything therefore hinges on the heart.

This makes clear the wisdom in the words of Allah Most High:

“Have they not travelled through the land, so that they might have hearts with which to reason or ears with which to hear?”

Here He does not even mention the eye, as He does in the preceding verses, because the discussion concerns unseen matters and wisdom discerned from the outcomes of events—matters beyond the scope of eyesight. Similar are His words:

“Or do you think that most of them hear or reason?”

The reality of the matter becomes clear in His words:

“Indeed, in that is a reminder for whoever has a heart or lends an ear while fully attentive.”

Those who are granted wisdom and benefit from knowledge fall into two categories. One person recognizes the truth for himself, accepts it, and follows it, without needing anyone to call him to it. This is the person who has a heart.

Another does not understand it for himself, but needs someone to teach him, explain it to him, admonish him, and instil proper conduct in him. Such a person listens attentively, and thus:

“lends an ear while fully attentive.”

That is, his heart is present, not absent. As Mujāhid said:

“He was given knowledge, and it became a reminder for him.”

His following words also become clear:

“And among them are those who listen to you. Can you then make the deaf hear, even if they do not