Ar-Raheem is a more specific mercy towards the believers. For
example, the mercy that descends during Ramadan is one only
Muslims who believe in Ramadan can enjoy. And Allah (swt) tells
us in the Qur’an,
هُوَ الَّذِي يُصَلِّي عَلَيْكُمْ وَمَلَائِكَتُهُ لِيُخْرِجَكُم مِّنَ الظُّلُمَاتِ إِلَى النُّورِ ۚ وَكَانَ بِالْمُؤْمِنِينَ رَحِيمًا – 33:43
It is He who confers blessing upon you, and His angels [ask Him to do so] that He may bring you out from darknesses into the light. And ever is He, to the believers, Merciful.