كَلَّا ۖ بَلْ ۜ رَانَ عَلَىٰ قُلُوبِهِم مَّا كَانُوا يَكْسِبُونَ
No! Rather, the stain has covered their hearts of that which they were earning. ~ Surah Mutaffifin 83:14
Hazrat Abu Hurairah Radiyallahu Anhu narrates that Rasulullah Sallallahu Alayhi Wasallam said: When the Mu’min sins, a black spot forms on his heart. If he makes Istighfaar and Taubah, the black mark is removed and his heart is purified. If he increases his sin, the black mark increases. This is the corrosion of the heart spoken of by Allah Ta’ala (in the Qur’aan) ~ Tirmidhi
Hazrat Umar ibn Al Khattab Radiyallahu Anhu has mentioned, “Some Evil Effects that are Connected to a Sin” :
• A person who commits sins, distances himself away from Jannah and gains proximity to Jahannum.
• A person pollutes his once pure soul with sin (and contaminates his Baatin).
Hadhrat Anas Bin Malik Radiyallahu Anhu narrates that Rasulullah Sallallahu Alayhi Wasallam said: “Should I not show you your sickness and its remedy? Your sickness is sinning and your remedy is to seek forgiveness (Istighfaar) ~ Baihaqi