Surah Al-Kahf, Verse 2

قَيِّمٗا لِّيُنذِرَ بَأۡسٗا شَدِيدٗا مِّن لَّدُنۡهُ وَيُبَشِّرَ ٱلۡمُؤۡمِنِينَ ٱلَّذِينَ يَعۡمَلُونَ ٱلصَّٰلِحَٰتِ أَنَّ لَهُمۡ أَجۡرًا حَسَنٗا٢

qayyiman liyundhira basan shadīdan min ladun'hu wayubashira l-mu'minīna alladhīna yaʿmalūna l-ṣāliḥāti anna lahum ajran ḥasanan

[He has made it] straight, to warn of severe punishment from Him and to give good tidings to the believers who do righteous deeds that they will have a good reward [i.e., Paradise].