If a person has with him hardness in his heart, then what are affairs that will soften the heart?
There is nothing better or more necessary (for softening the heart) than the Noble Qur’aan. It is what will soften the hearts. Allah -the Exalted and Sublime – said:
‘’Those who believe (in the Oneness of Allah – Islamic Monotheism), and whose hearts find rest in the remembrance of Allah, Verily, in the remembrance of Allah do hearts find rest.’’ [Surah al-Rad Verse 28]
So the Qur’aan is what will soften the hearts, which if Allah were to reveal it on a mountain, you would surely have seen it humbling itself and rending asunder by the fear of Allah;
‘’Had We sent down this Quran on a mountain, you would surely have seen it humbling itself and rending asunder by the fear of Allah.’’ [Suratul Hashr Verse 21]
Likewise sitting with the righteous and listening to The Qur’aan, (listening) to admonitions and reminders–this is what will soften the hearts.