Appears 5 times in the Quran.
6:125 فَمَن يُرِدِ ٱللَّهُ أَن يَهْدِيَهُۥ يَشْرَحْ صَدْرَهُۥ لِلْإِسْلَٰمِ وَمَن يُرِدْ أَن يُضِلَّهُۥ يَجْعَلْ صَدْرَهُۥ ضَيِّقًا حَرَجًا كَأَنَّمَا يَصَّعَّدُ فِى ٱلسَّمَآءِ كَذَٰلِكَ يَجْعَلُ ٱللَّهُ ٱلرِّجْسَ عَلَى ٱلَّذِينَ لَا يُؤْمِنُونَ
Therefore (for) whomsoever Allah intends that He would guide him aright, He expands his breast for Islam, and (for) whomsoever He intends that He should cause him to err, He makes his breast strait and narrow as though he were ascending upwards; thus does Allah lay uncleanness on those who do not believe.
16:106 مَن كَفَرَ بِٱللَّهِ مِنۢ بَعْدِ إِيمَٰنِهِۦٓ إِلَّا مَنْ أُكْرِهَ وَقَلْبُهُۥ مُطْمَئِنٌّۢ بِٱلْإِيمَٰنِ وَلَٰكِن مَّن شَرَحَ بِٱلْكُفْرِ صَدْرًا فَعَلَيْهِمْ غَضَبٌ مِّنَ ٱللَّهِ وَلَهُمْ عَذَابٌ عَظِيمٌ
He who disbelieves in Allah after his having believed, not he who is compelled while his heart is at rest on account of faith, but he who opens (his) breast to disbelief-- on these is the wrath of Allah, and they shall have a grievous chastisement.
He said: O my Lord! Expand my breast for me,
39:22 أَفَمَن شَرَحَ ٱللَّهُ صَدْرَهُۥ لِلْإِسْلَٰمِ فَهُوَ عَلَىٰ نُورٍ مِّن رَّبِّهِۦ فَوَيْلٌ لِّلْقَٰسِيَةِ قُلُوبُهُم مِّن ذِكْرِ ٱللَّهِ أُو۟لَٰٓئِكَ فِى ضَلَٰلٍ مُّبِينٍ
What! is he whose heart Allah has opened for Islam so that he is in a light from his Lord (like the hard-hearted)? Nay, woe to those whose hearts are hard against the remembrance of Allah; those are in clear error.
Have We not expanded for you your breast,