Ali 'Imran 3:88

وَمَن يَبْتَغِ غَيْرَ الْإِسْلَامِ دِينًا فَلَن يُقْبَلَ مِنْهُ وَهُوَ فِي الْآخِرَةِ مِنَ الْخَاسِرِينَ

And whoever desires other than Islam as religion - never will it be accepted from him, and he, in the Hereafter, will be among the losers.

كَيْفَ يَهْدِي اللَّهُ قَوْمًا كَفَرُوا بَعْدَ إِيمَانِهِمْ وَشَهِدُوا أَنَّ الرَّسُولَ حَقٌّ وَجَاءَهُمُ الْبَيِّنَاتُ ۚ وَاللَّهُ لَا يَهْدِي الْقَوْمَ الظَّالِمِينَ

How shall Allah guide a people who disbelieved after their belief and had witnessed that the Messenger is true and clear signs had come to them? And Allah does not guide the wrongdoing people.

أُولَـٰئِكَ جَزَاؤُهُمْ أَنَّ عَلَيْهِمْ لَعْنَةَ اللَّهِ وَالْمَلَائِكَةِ وَالنَّاسِ أَجْمَعِينَ

Those - their recompense will be that upon them is the curse of Allah and the angels and the people, all together,

إِلَّا الَّذِينَ تَابُوا مِن بَعْدِ ذَٰلِكَ وَأَصْلَحُوا فَإِنَّ اللَّهَ غَفُورٌ رَّحِيمٌ

Except for those who repent after that and correct themselves. For indeed, Allah is Forgiving and Merciful.

إِنَّ الَّذِينَ كَفَرُوا بَعْدَ إِيمَانِهِمْ ثُمَّ ازْدَادُوا كُفْرًا لَّن تُقْبَلَ تَوْبَتُهُمْ وَأُولَـٰئِكَ هُمُ الضَّالُّونَ

Indeed, those who reject the message after their belief and then increase in disbelief - never will their [claimed] repentance be accepted, and they are the ones astray.

إِنَّ الَّذِينَ كَفَرُوا وَمَاتُوا وَهُمْ كُفَّارٌ فَلَن يُقْبَلَ مِنْ أَحَدِهِم مِّلْءُ الْأَرْضِ ذَهَبًا وَلَوِ افْتَدَىٰ بِهِ ۗ أُولَـٰئِكَ لَهُمْ عَذَابٌ أَلِيمٌ وَمَا لَهُم مِّن نَّاصِرِينَ

Indeed, those who disbelieve and die while they are disbelievers - never would the [whole] capacity of the earth in gold be accepted from one of them if he would [seek to] ransom himself with it. For those there will be a painful punishment, and they will have no helpers.