Word patterns
Al-Raḥīm and al-Raḥmān
A Grammatical Benefit Behind الرَّحِيمُ and الرَّحْمٰنُ
Dr V. ʿAbd al‑Raḥīm (رَحِمَهُ اللهُ) explains that the Name of Allāh الرَّحِيمُ is on the pattern فَعِيلٌ, and this pattern signifies an inherent quality, as in:
كَرِيمٌ، سَخِيٌّ، جَلِيلٌ
Whereas الرَّحْمٰنُ is on the pattern فَعْلَانُ, and this pattern signifies a quality that is manifested in time and space, as in:
غَضْبَانُ، سَكْرَانُ، عَطْشَانُ
So الرَّحِيمُ points to the inherent quality of mercy in Allāh سُبْحَانَهُ وَتَعَالَى, and الرَّحْمٰنُ to the manifestation of His quality of mercy in time and space.
— Dr V. ʿAbd al‑Raḥīm (رَحِمَهُ اللهُ), Selections from the Glorious Qurʾān with Lexical and Grammatical Notes
Dr V. ʿAbd al‑Raḥīm (رَحِمَهُ اللهُ) explains that the Name of Allāh الرَّحِيمُ is on the pattern فَعِيلٌ, and this pattern signifies an inherent quality, as in:
كَرِيمٌ، سَخِيٌّ، جَلِيلٌ
Whereas الرَّحْمٰنُ is on the pattern فَعْلَانُ, and this pattern signifies a quality that is manifested in time and space, as in:
غَضْبَانُ، سَكْرَانُ، عَطْشَانُ
So الرَّحِيمُ points to the inherent quality of mercy in Allāh سُبْحَانَهُ وَتَعَالَى, and الرَّحْمٰنُ to the manifestation of His quality of mercy in time and space.
— Dr V. ʿAbd al‑Raḥīm (رَحِمَهُ اللهُ), Selections from the Glorious Qurʾān with Lexical and Grammatical Notes