The Prohibition of taking the Idolators as Supporters, even with Relatives
Allah says;
يَا أَيُّهَا الَّذِينَ امَنُواْ لَا تَتَّخِذُواْ ابَاءكُمْ وَإِخْوَانَكُمْ أَوْلِيَاء إَنِ اسْتَحَبُّواْ الْكُفْرَ عَلَى الاِيمَانِ وَمَن يَتَوَلَّهُم مِّنكُمْ فَأُوْلَـيِكَ هُمُ الظَّالِمُونَ
O you who believe! Take not as supporters your fathers and your brothers if they prefer disbelief to belief. And whoever of you befriends them, then he is one of the wrongdoers.
Allah commands shunning the disbelievers, even if they are one's parents or children, and prohibits taking them as supporters if they choose disbelief instead of faith.
Allah warns,
لااَّ تَجِدُ قَوْماً يُوْمِنُونَ بِاللَّهِ وَالْيَوْمِ الااٌّخِرِ يُوَادُّونَ مَنْ حَأدَّ اللَّهَ وَرَسُولَهُ وَلَوْ كَانُواْ ءَابَأءَهُمْ أَوْ أَبْنَأءَهُمْ أَوْ إِخْوَنَهُمْ أَوْ عَشِيرَتَهُمْ أُوْلَـيِكَ كَتَبَ فِى قُلُوبِهِمُ الااِيمَـنَ وَأَيَّدَهُمْ بِرُوحٍ مِّنْهُ وَيُدْخِلُهُمْ جَنَّـتٍ تَجْرِى مِن تَحْتِهَا الااٌّنْهَـرُ
You will not find any people who believe in Allah and the Last Day, making friendship with those who oppose Allah and His Messenger, even though they were their fathers or their sons or their brothers or their kindred (people). For such He has written (predetermined) faith in their hearts, and strengthened them with a Ruh (proof, light and true guidance) from Himself. And He will admit them to Gardens (Paradise) under which rivers flow. (58;22)
Al-Hafiz Al-Bayhaqi recorded that Abdullah bin Shawdhab said,
"The father of Abu Ubaydah bin Al-Jarrah was repeatedly praising the idols to his son on the day of Badr, and Abu Ubaydah kept avoiding him. When Al-Jarrah persisted, his son Abu Ubaydah headed towards him and killed him. Allah revealed this Ayah in his case,
لااَّ تَجِدُ قَوْماً يُوْمِنُونَ بِاللَّهِ وَالْيَوْمِ الااٌّخِرِ يُوَادُّونَ مَنْ حَأدَّ اللَّهَ وَرَسُولَهُ
You will not find any people who believe in Allah and the Last Day, making friendship with those who oppose Allah and His Messenger." (58;22)
Allah commanded His Messenger to warn those who prefer their family, relatives or tribe to Allah, His Messenger and Jihad in His cause