What is the difference between ar-Rahman and ar-Rahim?
Two divine names from one root, read together in every basmala: how the two Arabic forms differ, how wide each mercy is, and why one of them is never used of anyone but God.
Every chapter of the Quran but one opens with the same line, and a Muslim says it in every unit of prayer:
In the name of Allah, the Entirely Merciful, the Especially Merciful.
Both names come from one root, r-h-m, mercy. Sahih International renders them "the Entirely Merciful, the Especially Merciful". Why are both there? Is the second emphasis, or does it say something the first does not?
The commentaries below are in Arabic; the renderings are mine.
Mercy first, then the forms
Tafsir al-Mizan begins with the root rather than the two words. Tabataba’i notes that mercy as we know it is something felt — a state that comes over the heart at the sight of someone lacking what would make them whole, and moves a person to supply it. Analysed, he says, that comes down to giving, to supplying what is needed; and it is in that sense that God is described by mercy.
The difference is in the form, not the meaning
Then the distinction itself, which is grammatical. Rahman is built on the pattern fa‘lan, an intensive form indicating abundance. Rahim is on the pattern fa‘il, an adjectival form indicating what is fixed and lasting. So, he writes, it suits ar-Rahman to indicate an abundant mercy poured out on believer and unbeliever alike — the general mercy; and it suits ar-Rahim to indicate a lasting favour and an abiding mercy given to the believer. Hence what is often said: ar-Rahman covers everyone, ar-Rahim is particular to those who believe.
The same reading, in one sentence
Al-Tafsir al-Muyassar, on the third verse of Al-Fatihah, gives it as briefly as it can be given: ar-Rahman, the One whose mercy encompasses all creation; ar-Rahim, to the believers — and both are names of God.
The Entirely Merciful, the Especially Merciful,
Why are they repeated in Al-Fatihah?
The two names appear in the opening line and then again three verses later in the same short surah. Tafsir al-Safi reports one explanation offered for this: that the repetition draws attention, among the attributes listed, to what makes God deserving of the praise the surah has just given Him.
The Quran’s own usage
The pattern holds in how the two names are used. Ar-Rahman appears where the whole of creation is in view — as at the head of the surah named after it:
The Most Merciful
Taught the Qur'an,
(Ar-Rahman 55:1, Ar-Rahman 55:2)
And the breadth of that general mercy is stated outright:
My mercy encompasses all things.
Against which ar-Rahim turns up where believers in particular are meant:
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.
One more difference, less often mentioned
Ar-Rahman is used of no one but God — so much so that the Quran puts it beside the name Allah itself as an equally valid way of calling on Him:
Say, "Call upon Allah or call upon the Most Merciful. Whichever [name] you call - to Him belong the best names." And do not recite [too] loudly in your prayer or [too] quietly but seek between that an [intermediate] way.
Rahim, by contrast, is applied in the Quran to someone other than God. The last verses of At-Tawbah describe the Prophet with it:
There has certainly come to you a Messenger from among yourselves. Grievous to him is what you suffer; [he is] concerned over you and to the believers is kind and merciful.
In short
Ar-Rahman is a wide, abundant mercy reaching all of creation in their very existence. Ar-Rahim is a settled, lasting mercy given to those who believe, and it concerns where they end up. The two are set at the head of nearly every surah so that the first thing a reader meets is both at once: the door is wide, and what waits at the end of the road holds.
Read Al-Fatihah and Ar-Rahman.
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