The Family of Imran
إِنَّ ٱلَّذِينَ ٱشْتَرَوُا۟ ٱلْكُفْرَ بِٱلْإِيمَـٰنِ لَن يَضُرُّوا۟ ٱللَّهَ شَيْـًٔا وَلَهُمْ عَذَابٌ أَلِيمٌ
Indeed, those who purchase disbelief [in exchange] for faith - never will they harm Allah at all, and for them is a painful punishment.
Nearby ayahs help place verse 3:177 in sequence and meaning.
إِنَّمَا ذَٰلِكُمُ ٱلشَّيْطَـٰنُ يُخَوِّفُ أَوْلِيَآءَهُۥ فَلَا تَخَافُوهُمْ وَخَافُونِ إِن كُنتُم مُّؤْمِنِينَ
That is only Satan who frightens [you] of his supporters. So fear them not, but fear Me, if you are [indeed] believers.
وَلَا يَحْزُنكَ ٱلَّذِينَ يُسَـٰرِعُونَ فِى ٱلْكُفْرِ ۚ إِنَّهُمْ لَن يَضُرُّوا۟ ٱللَّهَ شَيْـًٔا ۗ يُرِيدُ ٱللَّهُ أَلَّا يَجْعَلَ لَهُمْ حَظًّا فِى ٱلْـَٔاخِرَةِ ۖ وَلَهُمْ عَذَابٌ عَظِيمٌ
And do not be grieved, [O Muhammad], by those who hasten into disbelief. Indeed, they will never harm Allah at all. Allah intends that He should give them no share in the Hereafter, and for them is a great punishment.
وَلَا يَحْسَبَنَّ ٱلَّذِينَ كَفَرُوٓا۟ أَنَّمَا نُمْلِى لَهُمْ خَيْرٌ لِّأَنفُسِهِمْ ۚ إِنَّمَا نُمْلِى لَهُمْ لِيَزْدَادُوٓا۟ إِثْمًا ۚ وَلَهُمْ عَذَابٌ مُّهِينٌ
And let not those who disbelieve ever think that [because] We extend their time [of enjoyment] it is better for them. We only extend it for them so that they may increase in sin, and for them is a humiliating punishment.
مَّا كَانَ ٱللَّهُ لِيَذَرَ ٱلْمُؤْمِنِينَ عَلَىٰ مَآ أَنتُمْ عَلَيْهِ حَتَّىٰ يَمِيزَ ٱلْخَبِيثَ مِنَ ٱلطَّيِّبِ ۗ وَمَا كَانَ ٱللَّهُ لِيُطْلِعَكُمْ عَلَى ٱلْغَيْبِ وَلَـٰكِنَّ ٱللَّهَ يَجْتَبِى مِن رُّسُلِهِۦ مَن يَشَآءُ ۖ فَـَٔامِنُوا۟ بِٱللَّهِ وَرُسُلِهِۦ ۚ وَإِن تُؤْمِنُوا۟ وَتَتَّقُوا۟ فَلَكُمْ أَجْرٌ عَظِيمٌ
Allah would not leave the believers in that [state] you are in [presently] until He separates the evil from the good. Nor would Allah reveal to you the unseen. But [instead], Allah chooses of His messengers whom He wills, so believe in Allah and His messengers. And if you believe and fear Him, then for you is a great reward.