And Allah said in the Quran:Surah Qaf 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]. (37)” ( 50:37 )
And said:Surah Qaf V.31 -33
وَأُزْلِفَتِ الْجَنَّةُ لِلْمُتَّقِينَ غَيْرَ بَعِيدٍ ﴿٣١﴾ هَٰذَا مَا تُوعَدُونَ لِكُلِّ أَوَّابٍ حَفِيظٍ ﴿٣٢﴾ مَّنْ خَشِيَ الرَّحْمَٰنَ بِالْغَيْبِ وَجَاءَ بِقَلْبٍ مُّنِيبٍ ﴿٣٣﴾
And Paradise will be brought near to the righteous, not far, (31) [It will be said], "This is what you were promised - for every returner [to Allah] and keeper [of His covenant] (32) Who feared the Most Merciful unseen and came with a heart returning [in repentance]. (33).” ( 50: 31 -33)
Therefore, the above verses make it explicit that health of a person is related to his heart's condition and his eternal salvation depends upon his return to God-Almighty with a pure and humble heart. On the other side the Holy Qur’an introduces some examples of hearts which are sick as follows:Surah Al Baqara V.10
فِي قُلُوبِهِم مَّرَضٌ فَزَادَهُمُ اللَّهُ مَرَضًا ﴿١٠﴾
“In their hearts is a disease, and God increaseth their disease. ( 2:10 )
And said: Surah Tawba V.125
وَأَمَّا الَّذِينَ فِي قُلُوبِهِم مَّرَضٌ فَزَادَتْهُمْ رِجْسًا إِلَىٰ رِجْسِهِمْ وَمَاتُوا وَهُمْ كَافِرُونَ ﴿١٢٥﴾
“But as for those in whose hearts is disease, it only addeth wickedness to their wickedness. ( 9:125 )