What is Sharah-e-Sadr or Inshirah-us-Sadr

أَفَمَن شَرَحَ اللَّـهُ صَدْرَهُ لِلْإِسْلَامِ فَهُوَ عَلَىٰ نُورٍ مِّن رَّبِّهِ

[Az-Zumar; 39:22]
So is one whose breast Allah has expanded to [accept] Islam and he is upon a light from his Lord
Allah swt in Qur’an-e-Karim has said:

أَفَمَن شَرَحَ اللَّـهُ صَدْرَهُ لِلْإِسْلَامِ فَهُوَ عَلَىٰ نُورٍ مِّن رَّبِّهِ

as for that for whom Allah swt has Expanded his breast for the Deen of Islam; for iman in Allah swt and Syedina Rasoolullah saw -then this person is upon a noor from their Rabb
This is what is known in Arabic as Inshirah-us-Sadr or Sharh-e-Sudoor; in Urdu sometimes its reffered to as Sharh-e-Sadr. This is that expanding of the breast with a Nur from Allah swt.
What does this mean?
Different Mufassiroon have written many things over here.
-> Some say that the Noor is the Noor of Hidaya
-> Some say that the Noor is the Noor of Iman
-> Some say that the Noor is the Noor of Qur’an
-> Some say that the Noor is the Noor of Sunnah-e-Nabi alaih-e-salam
All of these things are mentioned, that whenever a person’s heart or breast is expanded by Allah swt to be on the Deen- they are on a Noor. They enter into a Noor. And where did that noor come from?

نُورٍ مِّن رَّبِّهِ

That is a Noor that came to them from their Rabb; from their Allah swt
It means anyone of us who views oneself as a Muslim – we should think that we are on that noor ; that we’re inside that noor; that we want to do hifazat of that noor;that we want to acquire, preserve and protect that noor and we want to make sure not to do anything of our own choice through which we may lose even one drop of that noor.

Hadith regarding explanation of Sharh-e-Sadr:

وَرَوَى مَرَّة عَنْ اِبْن مَسْعُود قَالَ : قُلْنَا يَا رَسُول اللَّه قَوْله تَعَالَى : ” أَفَمَنْ شَرَحَ اللَّه صَدْره لِلْإِسْلَامِ فَهُوَ عَلَى نُور مِنْ رَبّه “

It comes in Hadith that the Syeddina Rasulullah saw was once asked regarding this ayah; syeddina Abdullah ‘ibn masood ra mentions that when this verse was revealed; the Sahaba Karaam asked the Prophet saw:

كَيْف اِنْشَرَحَ صَدْره ؟

(that Ya Rasulallah saw!) How is it that this person’s breast gets expanded(with this nur)?

قَالَ : إِذَا دَخَلَ النُّور الْقَلْب اِنْشَرَحَ وَانْفَتَحَ

Prophet saw said: when the noor from Allah swt enters their Qalb; enters into their spiritual heart; in the heart of their rooh then their heart expands and becomes opened up

قُلْنَا : يَا رَسُول اللَّه وَمَا عَلَامَة ذَلِكَ ؟

Sahaba ra asked: What is the sign that this person receives this noor; this Sharh-e-Sadr

(قَالَ : الْإِنَابَة إِلَى دَار الْخُلُود وَالتَّجَافِي عَنْ دَار الْغُرُور وَالِاسْتِعْدَاد لِلْمَوْتِ قَبْل نُزُوله )

الْإِنَابَة إِلَى دَار الْخُلُود

Rasoolullah saw said that (once the noor enters their heart) all of their focus, yearning aspiration and striving is for the aakhirah; for the everlasting hereafter; for the eternal home in which they will dwell in

وَالتَّجَافِي عَنْ دَار الْغُرُور

and now they abstain from/refrain from/ or are uninterested in this world of deception

دَار الْغُرُور

This is how Rasoolullah saw is explaining this world that it is the world of deception;the world of illusion;the world of delusion – just like when a person sees a mirage in the desert; when they realize that it is fake, then they are concerned with the rest of their journey

وَالِاسْتِعْدَاد لِلْمَوْتِ قَبْل نُزُوله

and they’re prepared for death before death overtakes them; they’re ready for death
So, these were the signs that Syeddina Rasoolullah saw mentions regarding a person who has sharhe sadr
This hadith was narrated by Imam Tirmidhi eah in his Jaame’
Asbaab-e-Inshiraah-us-Sadr
Hafiz Ibn-al-Qayyim has written in detail about the different means and processes by which we can get this inshiraahe sadr in his book, “Zaad-ul-ma’aad?” We’ll just go through them briefly.
- Iman
What does iman mean? lest maybe some if us must be thinking we already have iman
Iman means that whatever Syeddina Rasoolullahi saw told us (whether that be Qur’an or authentically transmitted hadith); whatever knowledge that has come to us by means of Rasoolullah saw– to have iman in that.
Imam al-Ghazali rah he actually made nabuwwah the essence of iman
Because even our belief in Allah swt is because Syeddina Rasoolullahi saw told us that Allah swt exists! Our belief that the Qur’an is authentic is because Rasoolullah saw told us that Qur’an is the word of Allah swt; Our belief in Jannah, Jahannam, Angels- all of that is because Syeddina Rasoolullahi saw told us that all of these things are true – therefore in our heart we believe that all of these things are true.
So, to believe in it entirely; absolutely with certain conviction in our heart – tasdeeq bil Qalb- that is called Iman. And, the person who has that feeling is called a Mo’min.
Allah swt has explained another aspect of Iman in Qur’an

الَّذِينَ يُؤْمِنُونَ بِالْغَيْبِ

[Al-Baqarah; 2:3]
That they are people who believe in the unseen
- They don’t ask for a hujjah; daleel; proof; logic and demonstration
- They believe in Allah swt- they don’t need to know things like what people ask today: When will Qiyamah come? How will it come? What exactly is the nature of Jannah? What exactly is the nature of Jahannum? Who will be judged in what way?! – they don’t need to know these things and we are not mukallif for that(we have not been made responsible to know all of that) – Allah swt is the sole Malik of Yaum-ud-Din! He is the Judge! nowhere in Qur’an have we been asked to judge another person – What family they were born in/what family they were born in/what will be their outcome – we are not responsible for that; we don’t have to give those answers to anyone.
Yes, the things we do know for sure are that Allah swt Exists and Syeddina Rasoolullah saw was the last Prophet & Messenger and whatever Syeddina Rasoolullah saw said is absolutely true – that’s what we know and that’s what we have to offer – beyond that Allah swt has a lot of knowledge that He has not shared with us. That is not going to be the basis on which we can decide or assess the Deen of Islam.
So, without any daleel to have belief in what Syeddina Rasoolullah saw said – that’s what means to take someone as our nabi! This is why Allah swt Sent so many ambiya with miracles – nothing to do with logic; rationality; demonstration and proof – precisely to show people that a Prophet is that human being who you are going to believe and who you will follow blindly! That’s what it means to accept someone as our nabi – Nabi saw is not our professor; scholar; philosopher – he is our Prophet saw.
And, because he saw is our Nabi and Prophet saw we will absolutely unconditionally follow and believe in each and everything that he told us – that is what it means to have Iman
And, as much iman a person gets this iman then Allah swt Expands their breast; their spiritual heart – on this noor that comes from Allah swt.
Iman in the Oneness Allah swt; all the books; angels; life after death; the Day of Judgment
Only two types of human beings
In another place Allah swt Mentions Iman in Qur’an and He Makes it clear that there are only two types of human beings – either you have iman or you don’t have iman. This is one of those issues that is absolutely black and white in Qur’an – Allah swt Says:

هُوَ الَّذِي خَلَقَكُمْ فَمِنكُمْ كَافِرٌ وَمِنكُم مُّؤْمِنٌ

[At-Taghabun; 64:2]
That Allah swt is that Being who has created each and every one of you(O humanity) and from amongst you there will be some who are unbeliever and some who are believers
In another Ayah Allah swt Says:

فَمَن شَاءَ فَلْيُؤْمِن وَمَن شَاءَ فَلْيَكْفُرْ

[Al-Kahf; 18:29]
That whosoever wants let him adopt Iman and whosoever wants let him deny the existence of Allah swt; let him reject Allah swt; let him disbelieve in Allah swt
But, they are only two categories.

وَاللَّـهُ عَلِيمٌ بِذَاتِ الصُّدُورِ

And indeed Allah swt is extremely Aware and All-knowing of every single thing that you do – means that our actions are either going to be actions of Iman or actions of Kufr
Iman is reflected in our actions:
In other words, Iman is not just a feeling; Iman is reflected in our actions – our acts; deeds; sayings; feelings; thoughts – and Allah swt about each and every one of those things is Baseer. And, each ad everything we do will be tagged – either it is an act worthy of Iman; or an act unworthy of Iman; rejecting Iman; neglecting Iman i.e. an act of Kufr – not necessarily an atheist; not necessarily disbelieving in the existence of Allah swt – but Is this an ‘amal of a mo’min or is this an ‘amal of a ghair-mo’min? Is this person’s amal, adab and ikhlaq of a mo’min or that of a ghair momin? – every single thing will be classified in these two categories!
Allah swt’s Love for Believers and Enmity for disbelievers
Allah swt has so much love for the believers and He has enmity for the disbelievers. In other words, another thing that is black and white is how Allah swt Feels about these two choices; about these two types of beings!
That person who is a mo’min gets the Zaati muhabbah of Allah swt – the pure essential love of Allah swt. And, that person who chooses not to be a mo’min gets the uduwwa – personal enmity of Allah swt
Yes, that person who sees iman; knows iman but chooses to reject and deny Iman gets the personal enmity of Allah swt.
That’s why Allah swt Says in the Qur’an:

اللَّـهُ وَلِيُّ الَّذِينَ آمَنُوا

يُخْرِجُهُم مِّنَ الظُّلُمَاتِ إِلَى النُّورِ

That Allah swt Loves the people of Iman so much that He becomes their Wali; He becomes their intimate Loving, Protecting, Nurturing Friend and then personally directly He takes them out from all of the darknesses in their life into Noor – into the same noor that came in Sharah-e-Sadr – in the noor of hidaya; the noor of Deen.
And, Allah swt Says about the second group:

وَالَّذِينَ كَفَرُوا أَوْلِيَاؤُهُمُ الطَّاغُوتُ

And the people who disbelieve – who are their friends? Shaytan and his minions! That’s who they get as a wali. Its just two choices – either Allah swt is our Wali or Shaytan is our wali. And, what happens to those people?

يُخْرِجُونَهُم مِّنَ النُّورِ إِلَى الظُّلُمَاتِ

They take them out of the noor(the possibility of accepting iman) and they bring them into darkness(into sin).
[Al-Baqarah; 2:257]
King & Peasant Analogy
Now, imagine that if some king of the world told some peasant of the world that I am your wali Allahuakbar! The peasant would be stunned! He would think that the king has told me – the peasant; subject; slave – that I am your wali. He would be in a a state of ecstacy; he’d be overjoyed that the king has come and personally told me that He is my Wali and that He is going to take me out of every single issue into solution – Well, if that is true for a king then Allah swt is far far far greater than the king and in relative to Allah swt we are far far far lower than a peasant. So, imagine how happy a mo’min should be when Allah swt told him in the Qur’an:

اللَّـهُ وَلِيُّ الَّذِينَ آمَنُوا

This phrase “Allazeena aamanu” – this is who and what we are. And, many young men and women today – they don’t think about this. Because, they don’t feel their iman; they are not aware and conscious of their iman therefore they don’t feel the wilayat of Allah swt that is promised for the iman. Because they are neglectful and forgetful of the existence of their very iman; they are neglectful and forgetful of Allah swt’s Wilayah that is promised with that iman. Just leading lives that are hapless and heedless – unaware; lazy
And, in English they try to fool you – they call it: Happy go Lucky! Allahu akbar – Oh, he is not happy, he is very unhappy! And he is not lucky, he is very unlucky! It is an unhappy, unlucky, unfortunate, misfortunate, depraved and deprived existence when you don’t feel the noor of Iman and when you don’t get the noor of Allah swt’s wilayah.
This is why Shaykh Khuwaja Bayazeed Bustami rah he used to mention that Allah swt Loves the believers. So, somebody asked him how. He said that first you have to understand the principle of love. The principle of Muhabbah: There is a Muhib – a lover and a Mahboob – a beloved.
The principle of love is that whenever the lover gives something to theirbeloved- nomatter how much they give – they always think that I didn’t give enough; they always think that whatever I gave was nothing; was unworthy of my beloved; is just a trifle, minute, petty- mo matter how much they give. From the flipside, whatever they get from their beloved – even if it is very small, even if it is just a drop – because it came from their beloved they view it as immense, as of enormous value.
That’s why in our Madressah system, whenever a Teacher used to reward a student with one Rupee, he would take that one Rupee coin – and because it came from their teacher – it would mean more to them than receiving one-lac rupee.
So, when Shaykh Bayazeed Bustami rah explained this principle; he said look what Allah swt Says in Qur’an:

وَإِن تَعُدُّوا نِعْمَتَ اللَّـهِ لَا تُحْصُوهَا

[Ibrahim; 14:34]
That if you were to try to count the blessings of Allah swt – you will never be able to enumerate them, you will never be able to encompass them!
Unlimited blessings Allah swt has Given us. But, because He swt is our Lover and the principle of love is that whenever a lover gives something to their beloved no matter how enormous it may be, even in this case – infinite, they will view it as very small…that’s why Allah swt Says:

قُلْ مَتَاعُ الدُّنْيَا قَلِيلٌ

[An-Nisa; 4:77]
That Say, my beloved Messenger saw to them that: this whole dunya and everything in it is just a trifle. All the blessings Allah swt Gives us He views them as just a trifle.
And flipside was when the beloved gives something to the lover, even if its small the lover views it as something great. So, what is it that we offer Allah swt? It is our salah, ibadah, zikr, dua. Now what type of worship or remembrance can we offer to Allah swt? Extremely little; petty; insignificant; very few moments of our life! But, what does Allah swt say about that Zikr in Qur’an:

وَالذَّاكِرِينَ اللَّـهَ كَثِيرًا وَالذَّاكِرَاتِ

[Al-Ahzab; 33:35]
And, the male believers who remember Allah swt Kaseer(Abundantly) – so when Allah swt Mentions all of the bounties of this world that He Gave us, He used the word “qaleel” in Qur’an and when we remember Allah swt, no matter how small it may be, Allah swt Calls it kaseer in the Qur’an – So, it means that according to the principle of love actually Allah swt is the Lover and we are the beloved! As long as a person has iman and feels the feelings of iman and is able to preserve the noor of that iman and is able to keep their heart and breast expanded and full of that iman in their life.