Among what indicates the refutation of the Outward (Al-Zahir), and also the obligation of establishing it among the Opposites (Al-Addad), as well as the obligation of concealing the Inward (Al-Batin), is the demolition of the Wall—which symbolizes the refutation of outward sciences—and its re-establishment after its demolition so that none but its [worthy] people may discover the Treasure, which symbolizes the Inward Knowledge.

As the Almighty pointed to this meaning in Surah Al-Kahf, saying: {So they set out, until when they came to the people of a town, they asked its people for food, but they refused to offer them hospitality. And they found therein a wall about to collapse, so he [Al-Khidr] restored it. [Moses] said, "If you wished, you could have taken for it a payment "} (Al-Kahf: 77).

And His—the Almighty's—saying: {And as for the wall, it belonged to two orphan boys in the city, and there was beneath it a treasure for them, and their father had been righteous. So your Lord intended that they reach maturity and extract their treasure, as a mercy from your Lord. And I did it not of my own accord. That is the interpretation of that about which you could not have patience.} (Al-Kahf: 82).