The surah Maryam may be entitled the surah of (Allah's) Mercy, because the dominant and prevalent topic in this surah actually is the mercy الرحمة, Mercy of Allah, examples of it, seeking it, asking for it, paths that lead towards it, ways that are misleading, the mercy of the son with his mother or father etc..
And as the name ar-Rahmaan as a word expressing excess in the topic of mercy expresses this mercy in a much bigger and better manner than the name ar-Raheem could express, it seems logical to use this name in the surah more frequently to give this mercy a bigger emphasize. And for the same reasons the name ar-Rahmaan has a similar status like the name Allah itself.
In fact the surah actually started with this topic (speaking of people who were guided fear Allah):
Kaf, Ha, Ya, 'Ayn, Sad. (1)
[This is] a mention of the mercy of your Lord to His servant Zechariah (2) (19:1-2)
And it ends with the opposite promise for those who are misguided and don't fear Allah:
So, [O Muhammad], We have only made Qur'an easy in the Arabic language that you may give good tidings thereby to the righteous and warn thereby a hostile people.(97)
And how many have We destroyed before them of generations? Do you perceive of them anyone or hear from them a sound? (98)(19:97-98)
Note that it is typical for Arabic eloquence to speak of one thing and its opposite to make a kind of comparison.
Among the tafssirs I've consulted (ibn Kathir, al-Qurtubi, al-Kashaf and others) only ibn 'Ashur pointed at the relationship between ar-Rhamah or ar-Rahmaan and this surah in his introdcution for the surah in his tafssir at-Tahrir wa at-Tanwir التحرير والتنوير (see )saying:
In the following I'll translate from Arabic language, as these translations are of my own take them with the necessary care!
وقد تكرر في هذه السورة صفة الرحمن ست عشرة مرة ، وذكر اسم الرحمة أربع مرات ، فأنبأ بأن من مقاصدها تحقيق وصف الله [ ص: 60 ] تعالى بصفة الرحمن .
And in this surah the attribut ar-Rahmaan was repeated sixteen times, and the noun ar-Rahmah was mentioned four times. So HE informed as that among the objectives of this surah is the confirmation of attributing Allah exalted be HE with the attribute ar-Rahmaan.
والرد على المشركين الذين تقعروا بإنكار هذا الوصف كما حكى الله تعالى عنهم في قوله في سورة الفرقان وإذا قيل لهم اسجدوا للرحمن قالوا وما الرحمن .
And the refutation of the pagans who were dished by their rejection of this attribution as Allah the almighty informed (himself) from them in suart al-Furqan "And when it is said to them, "Prostrate to the Most Merciful," they say, "And what is the Most Merciful?"(25:60).
however he explained most of the gifts of Allah that were mentioned as Karamat for his prophets ()
On the meaning of ar-Rahmah الرحمة and both attributes of Allah related to it
The focus here will be on the Arabic word الرحمة in first place. As for the main difference between ar-Rahmaan and ar-Raheem it is that ar-Rahmaan expresses ar-Rahmah in a more general manner so it includes all meanings of ar-Raheem -whichis more special- and goes beyond that. Therefore the translation of the corresponding words in the Basmalah in the Sahih international translation is:
... the Entirely Merciful, the Especially Merciful. (See for example here)
One could write books or at least papers on the differences therfore this should be sufficient at this point.
Ar-Rahmah الرحمة in Arabic is expressing:
- affectionateness, sommiseration, deep sympathy, feeling, kindliness and tenderness.
- clemency, compassion, graciousness, kindness, leniency, lenity, mercy, pity and symapthy.
and both meanings may apply for ar-Rahmaan and ar-Raheem as both are the corresponding nouns (Rahmaan and Raheem the corresponding adjectives/attributes).
Maybe a more skilled (native) English speaker may show specific differences in certain verses where one meaning will apply more than another, but a general assignement would be wrong.
Therefore I'd say that saying, for example, ar-Rahmaan refers to benevolence while ar-Raheem refers to mercy sounds too narrow to me. But Allah knows best.
The occurrence of ar-Rahmaan in this surah
As for the huge amount of the name of Allah ar-Rahman الرحمن in this surah we must say it appears in:
- She said, "Indeed, I seek refuge in the Most Merciful from you, [so leave me], if you should be fearing of Allah ." (19:18)
- ...'Indeed, I have vowed to the Most Merciful abstention, so I will not speak today to [any] man.' " (19:26)
- O my father, do not worship Satan. Indeed Satan has ever been, to the Most Merciful, disobedient. (19:44)
- O my father, indeed I fear that there will touch you a punishment from the Most Merciful so you would be to Satan a companion [in Hellfire]." (19:45)
- ...When the verses of the Most Merciful were recited to them, they fell in prostration and weeping. (19:58)
- [Therein are] gardens of perpetual residence which the Most Merciful has promised His servants in the unseen. Indeed, His promise has ever been coming. (19:61)
- Then We will surely extract from every sect those of them who were worst against the Most Merciful in insolence. (19:69)
- Say, "Whoever is in error - let the Most Merciful extend for him an extension [in wealth and time] until, when they see that which they were promised - either punishment [in this world] or the Hour [of resurrection] - they will come to know who is worst in position and weaker in soldiers." (19:75)
- Has he looked into the unseen, or has he taken from the Most Merciful a promise? (19:78)
- On the Day We will gather the righteous to the Most Merciful as a delegation (19:85)
- None will have [power of] intercession except he who had taken from the Most Merciful a covenant.(19:87)
- And they say, "The Most Merciful has taken [for Himself] a son." (19:88)
- That they attribute to the Most Merciful a son. (19:91)
- And it is not appropriate for the Most Merciful that He should take a son. (19:92)
- There is no one in the heavens and earth but that he comes to the Most Merciful as a servant. (19:93)
- Indeed, those who have believed and done righteous deeds - the Most Merciful will appoint for them affection. (19:96)
Beside the main topic of Islam which is the uniqueness of Allah (Tawheed), which is certainly one of the main topics of this surah, the above verses are mainly showing the compatibility of the names Allah and the name ar-Rahamaan, which is confirmed in the verse:
Say, "Call upon Allah or call upon the Most Merciful. Whichever [name] you call - to Him belong the best names." (17:110)
In most cases one could easily replace ar-Rahmaan by Allah, without any change of the meaning: in the in fact you will find examples of this in the qur'an where Allah is used instead of ar-Rahmaan for example surat al-Ikhlass covers the meaning of the verses #12-#15 in the list above. Further these verse show also the uniqueness by correcting and rejecting the wrong claims abiout Allah having offspring... mainly by telling the story of 'Isa () and Maryam () or refering to it.
Examples of mercy in surah Maryam
This is a short walk through the surah from tafseer ibn Kathir in italic with some comments:
The surah beginns with the story of Zakariyya and his supplication for a son,
the acceptance of his supplication,
Zakkariyya's amazement after the acceptance of his supplication,
the sign of the pregnancy,
the birth of the boy and his characteristics,
Allah's mercy here is for example that he gave him a son in an old age and further gave him a sign for the pregnancy of his wife.
The surah then moves to the story of Maryam and Al-Masih ('Isa),
the conception and the birth,
Maryam with Al-Masih before the people, their rejection of her and his reply to them,
'Isa is the Servant of Allah and not His Son,
Note that in this part Allah's mercy may be explained by the example of the fetus speaking to his mother comforting her and guiding her in her trouble before birth. And further the new born defending his mother from the accusation of her relatives etc. Allah describes it:
And [made me] dutiful to my mother, and He has not made me a wretched tyrant. (19:32)
This by itself is/was a miracle which is not reported in the Torah or new Testament. As according to the Jewish Shari'a Maryam could have been accused for Zina and punished by stoning, only her speaking new born could save her!
The disbeliever's warning of the day of distress. Warning the disbelievers is actually an example of the Mercy of Allah.
The qur'an then starts to tell us about an example:
The reply of Ibrahim's father,
Ibraheem asking Allah to forgive his father is an example of mercy in this case of Ibraheem who -as a guided and Allah fearing person- fears for his father.
Allah gave Ibrahim Ishaq and Ya'qub,
This is similiar to the story of Zakaria'.
Mentioning Musa and Harun, Allah's mercy for Musa is sending him with the support of his brother Harun to Pharao.
later the qur'an starts mentioning other guided people, prophets and messengers sometimes without explicitly pointing at the Mercy in this story, but introducing them (and earlier Zakariyya, Maryam and Ibraheem etc. too) by referring to them as a mercy of Allah:
Mentioning Idris, the mercy here might be his high position.
These prophets are the chosen ones: a favour of Allah certainly is a mercy.
They were succeeded by Wicked People and Good People, from this point on one could summarize the rest of the surah as examples for good behavior, fear of Allah and guidance and examples of the opposite and further the promises for both sides. The discussion of positions of disbelievers and pagans: for example Allah having a son -which plays a big role here and might be a reason why the story of 'Isa and Maryam () has been mentioned-. The mercy here is that in fact by showing the different examples and showing the right path and its truth and the wrong path and its falseness is a kind of mercy here.
So on the whole this surah shows the mercy in specific cases and in general, be it Allah's mercy or mercy in a more general manner.
Something to check this post pretends that the name of 'isa ibn Maryam appears with the same amount in this surah.
Finally note that Maryam () is/was woman and mother, and we usually associate women with mothers and mothers with mercy as quote in the sahih hadith comparing Allah's mercy and the mercy of a mother (which seems to be among the highest kinds of mercy for humans):
... "Allah is more merciful to His slaves than this lady to her son."
(See for example her in Sahih al-Bukhari and Sahih Muslim)
See also: Hadith: Allah being more merciful to His slaves than a mother to her child
Further references (recommendations):
This article -in Arabic- on alukah.
And the fatwa -in Arabic- on islamqa #282612.