Question: Would listening to Surat Al-Kahf (the Cave, Qur'an, Ch. 18) make up for reciting it?
Answer: In the name of Allah. May Peace and Blessings of Allah be upon His Messenger Muḥammad. It is advisable to read Surat Al-Kahf on Friday's day and the night before it (Thursday's evening). The prophet (pbuh) said, “Whoever recites Surat Al-Kahf on Friday, Allah would grant him/her bright light until the next Friday.” (Narrated by Al-Ḥākim in his Al-Mustadrak)
The time of reciting Surat Al-Kahf starts from Thursday sunset to Friday sunset.
Whoever is illiterate, and listens to it, seeking the reward mentioned in its merit, s/he gets it, God willing; that is because the affordable act of worship has to substitute the unaffordable one, as the rule stated by scholars of jurisprudence goes.
However, if one is able to read Al-Kahf, s/he should do that, rather than just listen to it. That is because the reward is quoted specifically for reading, not for listening.
Maybe the wisdom of the merit of reading Surat Al-Kahf weekly is that it includes many lessons that every Muslim should contemplate, some of which are the following:
Allah supports those who believe in Him, submit to Him, follow His path, defend Him in ways that may be difficult for the human mind to comprehend. This is evident in the story of the People of the Cave. These young men believed in their Lord, and escaped from their city to protect their religion. So, they took refuge in a cave in the mountain. They stayed there for three hundred and nine years, then Then, Allah brought them back to life after that long period of death.
The surah also presents a certain concept to the believer, namely that a test may be made either by vengeance and misfortune, or provision and gifts. Allah says, “We test you with both evil and good as trial; and to Us you will be returned”. (Qur’ān, 21:35) We learn this lesson from Surat Al-Kahf through the story of the owner of two gardens who was so rich. However, instead of thanking Allah for such grace, he disbelieved in Him; so Allah caused it to disappear.
The surah also teaches us that knowledge is always proportional, and that no matter how much knowledge a person may have is still so little. Allah says, “Humankind, you have not been given of knowledge except a little.” (Qur’ān, 17:85) So, no matter how much knowledge a person may have, there can be someone more knowledgeable. Allah says, “Over every possessor of knowledge is one [more] knowing”. (Qur’ān, 12:76) We learn this lesson from Surat Al-Kahf through the story of Prophet Moses (pbuh) and our Master Al-Khedr. Allah notified us that the good servant, Al-Khedr, had a special type of knowledge although he was not known as a prophet. Although Moses (pbuh) was a prophet, he did not know about particular matters until he was told about them by that good servant.
The surah also teaches us that having an authority is a kind of great test. An authority possessor must make good use of such authority to protect his religion, nation and society from the dangers that surround them. We learn this lesson from Surat Al-Kahf through the story of Ḍhul-Qarnayn. This good king dominated the earth, east and west. He acted with justice over the entire world, and devoted his great authority to serve all humanity by building a fortified barrier that protected his people form the aggression of Gog and Magog.
Reading Surat Al-Kahf typically helps the believer to extract many lessons that contribute to shaping his/her life towards the path of righteousness; That is why it is advisable to be read every Friday.