The 'heart', in Quran is vocabulary, is not just a piece of flesh in your body, but it is the centre of all your feelings, emotions, motives, drives, aspirations, remembrance and attention. It is the heart which softens
Quran Surah Az Zumar 39: verse 23,
اللَّهُ نَزَّلَ أَحْسَنَ الْحَدِيثِ كِتَابًا مُّتَشَابِهًا مَّثَانِيَ تَقْشَعِرُّ مِنْهُ جُلُودُ الَّذِينَ يَخْشَوْنَ رَبَّهُمْ ثُمَّ تَلِينُ جُلُودُهُمْ وَقُلُوبُهُمْ إِلَىٰ ذِكْرِ اللَّهِ ۚ ذَٰلِكَ هُدَى اللَّهِ يَهْدِي بِهِ مَن يَشَاءُ ۚ وَمَن يُضْلِلِ اللَّهُ فَمَا لَهُ مِنْ هَادٍ ﴿٢٣﴾
Allah has sent down the best statement: a consistent Book wherein is reiteration. The skins shiver therefrom of those who fear their Lord; then their skins and their hearts relax at the remembrance of Allah. That is the guidance of Allah by which He guides whom He wills. And one whom Allah leaves astray - for him there is no guide. (23)
Or hardens.- Quran Surah Al Baqara 2: verse 74
ثُمَّ قَسَتْ قُلُوبُكُم مِّن بَعْدِ ذَٰلِكَ فَهِيَ كَالْحِجَارَةِ أَوْ أَشَدُّ قَسْوَةً ۚ وَإِنَّ مِنَ الْحِجَارَةِ لَمَا يَتَفَجَّرُ مِنْهُ الْأَنْهَارُ ۚ وَإِنَّ مِنْهَا لَمَا يَشَّقَّقُ فَيَخْرُجُ مِنْهُ الْمَاءُ ۚ وَإِنَّ مِنْهَا لَمَا يَهْبِطُ مِنْ خَشْيَةِ اللَّهِ ۗ وَمَا اللَّهُ بِغَافِلٍ عَمَّا تَعْمَلُونَ ﴿٧٤﴾
Then your hearts became hardened after that, being like stones or even harder. For indeed, there are stones from which rivers burst forth, and there are some of them that split open and water comes out, and there are some of them that fall down for fear of Allah. And Allah is not unaware of what you do.
It is the heart that goes blind and refuses to recognize the truth
Quran Surah Al Hajj 22: verse 46
أَفَلَمْ يَسِيرُوا فِي الْأَرْضِ فَتَكُونَ لَهُمْ قُلُوبٌ يَعْقِلُونَ بِهَا أَوْ آذَانٌ يَسْمَعُونَ بِهَا ۖ فَإِنَّهَا لَا تَعْمَى الْأَبْصَارُ وَلَٰكِن تَعْمَى الْقُلُوبُ الَّتِي فِي الصُّدُورِ ﴿٤٦﴾
So have they not traveled through the earth and have hearts by which to reason and ears by which to hear? For indeed, it is not eyes that are blinded, but blinded are the hearts which are within the breasts.
And it is the heart that inspires the function to reason and understand. Quran Surah Al Araf 7: verse 179;
وَلَقَدْ ذَرَأْنَا لِجَهَنَّمَ كَثِيرًا مِّنَ الْجِنِّ وَالْإِنسِ ۖ لَهُمْ قُلُوبٌ لَّا يَفْقَهُونَ بِهَا وَلَهُمْ أَعْيُنٌ لَّا يُبْصِرُونَ بِهَا وَلَهُمْ آذَانٌ لَّا يَسْمَعُونَ بِهَا ۚ أُولَٰئِكَ كَالْأَنْعَامِ بَلْ هُمْ أَضَلُّ ۚ أُولَٰئِكَ هُمُ الْغَافِلُونَ ﴿١٧٩﴾
And We have certainly created for Hell many of the jinn and mankind. They have hearts with which they do not understand, they have eyes with which they do not see, and they have ears with which they do not hear. Those are like livestock; rather, they are more astray. It is they who are the heedless.
Quran Surah Alhajj 22: verse 46;
أَفَلَمْ يَسِيرُوا فِي الْأَرْضِ فَتَكُونَ لَهُمْ قُلُوبٌ يَعْقِلُونَ بِهَا أَوْ آذَانٌ يَسْمَعُونَ بِهَا ۖ فَإِنَّهَا لَا تَعْمَى الْأَبْصَارُ وَلَٰكِن تَعْمَى الْقُلُوبُ الَّتِي فِي الصُّدُورِ ﴿٤٦﴾
So have they not traveled through the earth and have hearts by which to reason and ears by which to hear? For indeed, it is not eyes that are blinded, but blinded are the hearts which are within the breasts.
Quran Surah Qaf 50: verse 37
إِنَّ فِي ذَٰلِكَ لَذِكْرَىٰ لِمَن كَانَ لَهُ قَلْبٌ أَوْ أَلْقَى السَّمْعَ وَهُوَ شَهِيدٌ ﴿٣٧﴾
Indeed in that is a reminder for whoever has a heart or who listens while he is present [in mind].
In the heart, lies the root of all outward diseases
Quran Surah Al Maidah 5: verse 52;
فَتَرَى الَّذِينَ فِي قُلُوبِهِم مَّرَضٌ يُسَارِعُونَ فِيهِمْ يَقُولُونَ نَخْشَىٰ أَن تُصِيبَنَا دَائِرَةٌ ۚ فَعَسَى اللَّهُ أَن يَأْتِيَ بِالْفَتْحِ أَوْ أَمْرٍ مِّنْ عِندِهِ فَيُصْبِحُوا عَلَىٰ مَا أَسَرُّوا فِي أَنفُسِهِمْ نَادِمِينَ ﴿٥٢﴾
So you see those in whose hearts is disease hastening into [association with] them, saying, "We are afraid a misfortune may strike us." But perhaps Allah will bring conquest or a decision from Him, and they will become, over what they have been concealing within themselves, regretful.
It is the seat of all inner ills -Quran Surah Al Baqara 2: verse10.
فِي قُلُوبِهِم مَّرَضٌ فَزَادَهُمُ اللَّهُ مَرَضًا ۖ وَلَهُمْ عَذَابٌ أَلِيمٌ بِمَا كَانُوا يَكْذِبُونَ ﴿١٠﴾
In their hearts is disease, so Allah has increased their disease; and for them is a painful punishment because they [habitually] used to lie.
The heart is the abode of faith Quran Surah Al Maidah 5: verse 41
يَا أَيُّهَا الرَّسُولُ لَا يَحْزُنكَ الَّذِينَ يُسَارِعُونَ فِي الْكُفْرِ مِنَ الَّذِينَ قَالُوا آمَنَّا بِأَفْوَاهِهِمْ وَلَمْ تُؤْمِن قُلُوبُهُمْ ۛ وَمِنَ الَّذِينَ هَادُوا ۛ سَمَّاعُونَ لِلْكَذِبِ سَمَّاعُونَ لِقَوْمٍ آخَرِينَ لَمْ يَأْتُوكَ ۖ يُحَرِّفُونَ الْكَلِمَ مِن بَعْدِ مَوَاضِعِهِ ۖ يَقُولُونَ إِنْ أُوتِيتُمْ هَٰذَا فَخُذُوهُ وَإِن لَّمْ تُؤْتَوْهُ فَاحْذَرُوا ۚ وَمَن يُرِدِ اللَّهُ فِتْنَتَهُ فَلَن تَمْلِكَ لَهُ مِنَ اللَّهِ شَيْئًا ۚ أُولَٰئِكَ الَّذِينَ لَمْ يُرِدِ اللَّهُ أَن يُطَهِّرَ قُلُوبَهُمْ ۚ لَهُمْ فِي الدُّنْيَا خِزْيٌ ۖ وَلَهُمْ فِي الْآخِرَةِ عَذَابٌ عَظِيمٌ ﴿٤١﴾
O Messenger, let them not grieve you who hasten into disbelief of those who say, "We believe" with their mouths, but their hearts believe not, and from among the Jews. [They are] avid listeners to falsehood, listening to another people who have not come to you. They distort words beyond their [proper] usages, saying "If you are given this, take it; but if you are not given it, then beware." But he for whom Allah intends fitnah - never will you possess [power to do] for him a thing against Allah. Those are the ones for whom Allah does not intend to purify their hearts. For them in this world is disgrace, and for them in the Hereafter is a great punishment.
And hypocrisy. - Quran Surah At Tawba 9: verse 77
فَأَعْقَبَهُمْ نِفَاقًا فِي قُلُوبِهِمْ إِلَىٰ يَوْمِ يَلْقَوْنَهُ بِمَا أَخْلَفُوا اللَّهَ مَا وَعَدُوهُ وَبِمَا كَانُوا يَكْذِبُونَ ﴿٧٧﴾
So He penalized them with hypocrisy in their hearts until the Day they will meet Him - because they failed Allah in what they promised Him and because they [habitually] used to lie.
It is the heart, which is the centre of all that is good and bad, whether it be contentment and peace Quran Surah Ar Rad 13: verse 28,
الَّذِينَ آمَنُوا وَتَطْمَئِنُّ قُلُوبُهُم بِذِكْرِ اللَّهِ ۗ أَلَا بِذِكْرِ اللَّهِ تَطْمَئِنُّ الْقُلُوبُ ﴿٢٨﴾
Those who have believed and whose hearts are assured by the remembrance of Allah. Unquestionably, by the remembrance of Allah hearts are assured."
The strength to face afflictions Quran Surah At Taghabun 64: verse 11,
مَا أَصَابَ مِن مُّصِيبَةٍ إِلَّا بِإِذْنِ اللَّهِ ۗ وَمَن يُؤْمِن بِاللَّهِ يَهْدِ قَلْبَهُ ۚ وَاللَّهُ بِكُلِّ شَيْءٍ عَلِيمٌ ﴿١١﴾
No disaster strikes except by permission of Allah. And whoever believes in Allah - He will guide his heart. And Allah is Knowing of all things.
Mercy Quran Surah Al Hadid 57: verse 27,
ثُمَّ قَفَّيْنَا عَلَىٰ آثَارِهِم بِرُسُلِنَا وَقَفَّيْنَا بِعِيسَى ابْنِ مَرْيَمَ وَآتَيْنَاهُ الْإِنجِيلَ وَجَعَلْنَا فِي قُلُوبِ الَّذِينَ اتَّبَعُوهُ رَأْفَةً وَرَحْمَةً وَرَهْبَانِيَّةً ابْتَدَعُوهَا مَا كَتَبْنَاهَا عَلَيْهِمْ إِلَّا ابْتِغَاءَ رِضْوَانِ اللَّهِ فَمَا رَعَوْهَا حَقَّ رِعَايَتِهَا ۖ فَآتَيْنَا الَّذِينَ آمَنُوا مِنْهُمْ أَجْرَهُمْ ۖ وَكَثِيرٌ مِّنْهُمْ فَاسِقُونَ ﴿٢٧﴾
Then We sent following their footsteps Our messengers and followed [them] with Jesus, the son of Mary, and gave him the Gospel. And We placed in the hearts of those who followed him compassion and mercy and monasticism, which they innovated; We did not prescribe it for them except [that they did so] seeking the approval of Allah. But they did not observe it with due observance. So We gave the ones who believed among them their reward, but many of them are defiantly disobedient.
Brotherly love - Quran Surah Al Anfal 8: verse 63,
وَأَلَّفَ بَيْنَ قُلُوبِهِمْ ۚ لَوْ أَنفَقْتَ مَا فِي الْأَرْضِ جَمِيعًا مَّا أَلَّفْتَ بَيْنَ قُلُوبِهِمْ وَلَٰكِنَّ اللَّهَ أَلَّفَ بَيْنَهُمْ ۚ إِنَّهُ عَزِيزٌ حَكِيمٌ ﴿٦٣﴾
And brought together their hearts. If you had spent all that is in the earth, you could not have brought their hearts together; but Allah brought them together. Indeed, He is Exalted in Might and Wise.
God-Consciousness Quran Surah Al Hujurat 49: verse 3;
إِنَّ الَّذِينَ يَغُضُّونَ أَصْوَاتَهُمْ عِندَ رَسُولِ اللَّهِ أُولَٰئِكَ الَّذِينَ امْتَحَنَ اللَّهُ قُلُوبَهُمْ لِلتَّقْوَىٰ ۚ لَهُم مَّغْفِرَةٌ وَأَجْرٌ عَظِيمٌ ﴿٣﴾
Indeed, those who lower their voices before the Messenger of Allah - they are the ones whose hearts Allah has tested for righteousness. For them is forgiveness and great reward.
Quran Surah Al Hajj 22: verse 32;
ذَٰلِكَ وَمَن يُعَظِّمْ شَعَائِرَ اللَّهِ فَإِنَّهَا مِن تَقْوَى الْقُلُوبِ ﴿٣٢﴾
That [is so]. And whoever honors the symbols of Allah - indeed, it is from the piety of hearts.
Or, doubt and hesitation - Quran Surah At Tawba 9: verse 45,
إِنَّمَا يَسْتَأْذِنُكَ الَّذِينَ لَا يُؤْمِنُونَ بِاللَّهِ وَالْيَوْمِ الْآخِرِ وَارْتَابَتْ قُلُوبُهُمْ فَهُمْ فِي رَيْبِهِمْ يَتَرَدَّدُونَ ﴿٤٥﴾
Only those would ask permission of you who do not believe in Allah and the Last Day and whose hearts have doubted, and they, in their doubt, are hesitating.
Regrets - Quran Surah Al Imran 3: verse 156,
يَا أَيُّهَا الَّذِينَ آمَنُوا لَا تَكُونُوا كَالَّذِينَ كَفَرُوا وَقَالُوا لِإِخْوَانِهِمْ إِذَا ضَرَبُوا فِي الْأَرْضِ أَوْ كَانُوا غُزًّى لَّوْ كَانُوا عِندَنَا مَا مَاتُوا وَمَا قُتِلُوا لِيَجْعَلَ اللَّهُ ذَٰلِكَ حَسْرَةً فِي قُلُوبِهِمْ ۗ وَاللَّهُ يُحْيِي وَيُمِيتُ ۗ وَاللَّهُ بِمَا تَعْمَلُونَ بَصِيرٌ ﴿١٥٦﴾
O you who have believed, do not be like those who disbelieved and said about their brothers when they traveled through the land or went out to fight, "If they had been with us, they would not have died or have been killed," so Allah makes that [misconception] a regret within their hearts. And it is Allah who gives life and causes death, and Allah is Seeing of what you do.
And anger - Quran Surah At Tawba 9: verse 15.
وَيُذْهِبْ غَيْظَ قُلُوبِهِمْ ۗ وَيَتُوبُ اللَّهُ عَلَىٰ مَن يَشَاءُ ۗ وَاللَّهُ عَلِيمٌ حَكِيمٌ ﴿١٥﴾
And remove the fury in the believers' hearts. And Allah turns in forgiveness to whom He wills; and Allah is Knowing and Wise.
Finally it is, in reality, the way of the heart for which we shall be accountable, and only the one who brings before his God a sound and sincere heart will deserve to be saved.