Allah prohibited His believing servants from becoming supporters of the disbelievers, or to take them as comrades with whom they develop friendships, rather than the believers. Allah warned against such behavior when He said,

﴿وَمَن يَفْعَلْ ذَلِكَ فَلَيْسَ مِنَ اللَّهِ فِي شَىْءٍ﴾

(And whoever does that, will never be helped by Allah in any way) meaning, whoever commits this act that Allah has prohibited, then Allah will discard him. Similarly, Allah said,

﴿يأَيُّهَا الَّذِينَ ءَامَنُواْ لاَ تَتَّخِذُواْ عَدُوِّى وَعَدُوَّكُمْ أَوْلِيَآءَ تُلْقُونَ إِلَيْهِمْ بِالْمَوَدَّةِ﴾

(O you who believe! Take not My enemies and your enemies as friends, showing affection towards them), until,

﴿وَمَن يَفْعَلْهُ مِنكُمْ فَقَدْ ضَلَّ سَوَآءَ السَّبِيلِ﴾

(And whosoever of you does that, then indeed he has gone astray from the straight path.) ﴿60:1﴾. Allah said,

﴿يَـأَيُّهَا الَّذِينَ ءَامَنُواْ لاَ تَتَّخِذُواْ الْكَـفِرِينَ أَوْلِيَآءَ مِن دُونِ الْمُؤْمِنِينَ أَتُرِيدُونَ أَن تَجْعَلُواْ للَّهِ عَلَيْكُمْ سُلْطَاناً مُّبِيناً ﴾

(O you who believe! Take not for friends disbelievers instead of believers. Do you wish to offer Allah a manifest proof against yourselves) ﴿4:144﴾, and,

﴿يَـأَيُّهَا الَّذِينَ ءَامَنُواْ لاَ تَتَّخِذُواْ الْيَهُودَ وَالنَّصَـرَى أَوْلِيَآءَ بَعْضُهُمْ أَوْلِيَآءُ بَعْضٍ وَمَن يَتَوَلَّهُمْ مِّنكُمْ فَإِنَّهُ مِنْهُمْ﴾

(O you who believe! Take not the Jews and the Christians as friends, they are but friends of each other. And whoever befriends them, then surely, he is one of them.) ﴿5:51﴾.

Allah said, after mentioning the fact that the faithful believers gave their support to the faithful believers among the Muhajirin, Ansar and Bedouins,

﴿وَالَّذينَ كَفَرُواْ بَعْضُهُمْ أَوْلِيَآءُ بَعْضٍ إِلاَّ تَفْعَلُوهُ تَكُنْ فِتْنَةٌ فِى الاٌّرْضِ وَفَسَادٌ كَبِيرٌ ﴾

(And those who disbelieve are allies of one another, (and) if you do not behave the same, there will be Fitnah and oppression on the earth, and a great mischief and corruption.) ﴿8:73﴾.

Allah said next,

﴿إِلاَ أَن تَتَّقُواْ مِنْهُمْ تُقَـةً﴾

(unless you indeed fear a danger from them) meaning, except those believers who in some areas or times fear for their safety from the disbelievers. In this case, such believers are allowed to show friendship to the disbelievers outwardly, but never inwardly. For instance, Al-Bukhari recorded that Abu Ad-Darda' said, "We smile in the face of some people although our hearts curse them.'' Al-Bukhari said that Al-Hasan said, "The Tuqyah is allowed until the Day of Resurrection.'' Allah said,

﴿وَيُحَذِّرُكُمُ اللَّهُ نَفْسَهُ﴾

(And Allah warns you against Himself.) meaning, He warns you against His anger and the severe torment He prepared for those who give their support to His enemies, and those who have enmity with His friends,

﴿وَإِلَى اللَّهِ الْمَصِيرُ﴾

(And to Allah is the final return) meaning, the return is to Him and He will reward or punish each person according to their deeds.

﴿قُلْ إِن تُخْفُواْ مَا فِى صُدُورِكُمْ أَوْ تُبْدُوهُ يَعْلَمْهُ اللَّهُ وَيَعْلَمُ مَا فِى السَّمَـوَتِ وَمَا فِى الاٌّرْضِ وَاللَّهُ عَلَى كُلِّ شَىْءٍ قَدِيرٌ - يَوْمَ تَجِدُ كُلُّ نَفْسٍ مَّا عَمِلَتْ مِنْ خَيْرٍ مُّحْضَرًا وَمَا عَمِلَتْ مِن سُوءٍ تَوَدُّ لَوْ أَنَّ بَيْنَهَا وَبَيْنَهُ أَمَدَا بَعِيدًا وَيُحَذِّرُكُمُ اللَّهُ نَفْسَهُ وَاللَّهُ رَءُوفُ بِالْعِبَادِ ﴾

(29. Say: "Whether you hide what is in your breasts or reveal it, Allah knows it, and He knows what is in the heavens and what is in the earth. And Allah is able to do all things.'') (30. On the Day when every person will be confronted with the good he has done, and all the evil he has done, he will wish that there were a great distance between him and his evil. And Allah warns you against Himself and Allah is full of kindness with the servants.)