Since valleys are the channels through which torrents flow, they contain debris and other matter that the torrent encounters and carries along. This floats on the water’s surface as rising foam, heaped up as it flows. Beneath it, however, is the fresh, sweet water that gives life to the earth. The valley casts this debris onto its banks until none remains, while the water beneath it remains. With this water Allah Most High irrigates the earth, bringing life to lands, people, trees, and animals. The debris is swept away, discarded and cast onto the valley’s edge.

Such, too, are the knowledge and faith that He sends down into hearts, which receive them. As they mingle with the hearts, they stir up the debris of desires and the foam of false doubts within them, causing these to float to the surface, while knowledge, faith, and guidance settle deep within the hearts. This debris and foam continue to be swept away, disappearing little by little until they are entirely gone. Beneficial knowledge and pure faith remain in this heart, to which people come to drink, draw water, and enjoy abundance.

[Surah al-Ra‘d (13): verse 28]

“Those who believe and whose hearts find comfort in the remembrance of Allah. Surely in the remembrance of Allah do hearts find comfort.” (28)

Tranquillity means that the heart rests in something, free from agitation and anxiety. Hence the well-known report: “Truthfulness brings reassurance, while lying brings doubt.” That is, the listener’s heart is reassured by truthfulness and finds rest in it, whereas lying causes agitation and doubt. Likewise, the Prophet, may Allah bless him and grant him peace, said:

“Righteousness is that with which the heart is at ease.”

That is, the heart finds rest in it, and its agitation and anxiety subside.

There are two interpretations of “the remembrance of Allah” here.

The first is that it means the servant’s remembrance of his Lord, through which his heart finds reassurance and rest. When the heart becomes agitated and anxious, nothing can reassure it except the remembrance of Allah.

Those who hold this view then differed over its meaning. Some said that it refers to swearing oaths: when a believer swears to something, the hearts of other believers find rest and reassurance in his oath. This is reported from Ibn ‘Abbās, may Allah be pleased with them both.