Translation of the meanings Ayah 25 Surah Al-Kahf - English Translation - Dr. Waleed Bleyhesh Omary - The Noble Qur'an Encyclopedia

Ayah: 25

وَلَبِثُواْ فِي كَهۡفِهِمۡ ثَلَٰثَ مِاْئَةٖ سِنِينَ وَٱزۡدَادُواْ تِسۡعٗا

(25) ^[3797]They remained in their cave for three hundred years and ˹another˺ nine more added to them^[3798].

[3797] This nurturing interposition aside, God Almighty directs His Noble Messenger (ﷺ) to what is ‘nearer to guidedness’ by telling him in very precise terms the duration of their stay. This duration of their stay is of more significance than their number which gave rise to much argument (cf. al-Biqāʿī, Naẓm al-Durar).
[3798] The duration of their stay is given in both the solar calendar (300 years) and the lunar calendar (300 and nine more years) (cf. al-Māwardī, Ibn Kathīr, al-Biqāʿī, al-Shinqīṭī). The reason behind stating the date in the two calendars is to leave no doubt whatsoever in the minds of any party who use one or the other of these two where this piece of information comes from (cf. Ibn ʿĀshūr). Such is precise knowledge, based on Divine revelation, from that which is a far cry from it and which is based on jabbing in the dark.