Which verses show the importance of ‘Aql in Islam?

The Quran is filled with verses constantly reminding mankind of the blessing and responsibility that comes with having the distinguishing gift of ‘Aql, or discernment. Some examples of verses are as follows:

In Chapter 2, after detailing the legislated guidelines and etiquettes for an acceptable Hajj pilgrimage, as well as the prohibitions, Allah the Exalted says,

{... So, fear Me, oh people of sound reasoning.}

This encourages people of sound reasoning to follow the prescribed guidelines that their pilgrimage be accepted, and strikes fear into anyone who might even consider doing a distasteful act while in the midst of these sacred rituals.

In another verses, Allah says,

{Only those who reflect will be reminded}

This encourages those with sound reasoning to reflect deeply on what was mentioned in the previous and surrounding verses, to ascertain the benefit buried within.

and in yet another verse, Allah says:

{If it has been said to them, ‘follow what has been revealed by Allah’, they will say, ‘We will follow what we found our fathers followed.’ What, even if their forefathers had no proper spiritual discernment, and no guidance.}

This verse is a reprimand for those who use their misguided forefathers as an excuse for their missteps, and encourages them to use their good righteous sense to correct their ways, and encourage their remaining elders to do the same.