Guidance is in the heart.

Allah-Almighty said:Surah Taghabun V.11

1 ﴿ وَمَن يُؤْمِن بِاللَّهِ يَهْدِ قَلْبَهُ ۚ وَاللَّهُ بِكُلِّ شَيْءٍ عَلِيمٌ ﴾

“And whosoever believeth in Allah, He guideth his heart. And Allah is knower of all things.” (64:11)

And Allah said:Surah Qaf V.37

2 ﴿ شهيدوَهُوَ إِنَّ فِي ذَٰلِكَ لَذِكْرَىٰ لِمَن كَانَ لَهُ قَلْبٌ أَوْ أَلْقَى السَّمْعَ ﴾

“Indeed in that is a reminder for whoever has a heart or who listens while he is present [in mind]. (50: 37)

Negligence is also in the heart

Allah-Almighty said:Surah Al Khaf V.28

3 ﴿ وَلَا تُطِعْ مَنْ أَغْفَلْنَا قَلْبَهُ عَن ذِكْرِنَا وَاتَّبَعَ هَوَاهُ ﴾

“And obey not him whose heart we have made heedless of Our Remembrance, who followeth his own lust.” (18:28)