As-Salaamu-Alaikum.
In the name of Allah, the Most Gracious, the Most Merciful
Ibn Abidin said, And it is best to do so early on Friday, in order to rush to the good and to avoid forgetting.
[Ibn Abidin, Radd al-Muhtar, Bab al-Jumu`ah]
'Whoever recites Surat al-Kahf on Friday, light shall shine forth for him between the two Fridays.' (Haakim and Bayhaqi)
The islamic calendar day commences at the start of the night, meaning sunset. This means that if you say that you will do something on the night of the 15th, this means that you will do so after sunset following the day of the 14th.
Another Hadith
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Whoever commits ten verses from the beginning Surat al-Kahf will be protected from the Dajjal [Muslim]
Wisdom
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The wisdom behind it, as mentioned by hadith commentators such as Nawawi, Qurtubi, Qari, and others, is that:
a) There are tremendous signs and portents mentioned in these verses. However reads these regularly and ponders on their meanings with not be led astray by the Dajjal;
b) The surah as a whole has stories of the struggle between true belief in Allah and the realities of faith, and materialism. Reflecting on any of these
c) It is a secret whose knowledge Allah alone posses, and we have follow it because of the Prophet (Allah bless him and give him peace) guidance, with full certainty.
And Allah knows best.
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A Dua From Surah Khaf 18. Verse 10
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rabbana atina miladunka rahmatoww wahayyitlana min amrinarashada
"Our Lord! Bestow on us mercy from Yourself, and facilitate for us our
affair in the right way!"
