Al Wala Wal Bara
Al-wala wal-bara is a concept in Sunni Islam, meaning literally "loyalty and disavowal", which signifies loving and hating for the sake of Allah.
Al-wala wal-bara is referred to as
=> holding fast to all that is pleasing to God, and
=> withdrawing from and opposing all that is displeasing to Allah,
- for the sake of Allah.
This is for their calling towards something other than submission to Allah, whether on purpose or by nature of disbelief.
Loving for the sake of Allah means to love Allah and to show loyalty to him by following his Shariah. It means to love all that is good and permissible in the Quran and Sunnah:
This type of love requires one to defend Allah's dīn (religion) and to preserve it. It is to love those who are obedient to Allah and to defend and assist them.
Hating for the sake of Allah signifies showing anger towards those who oppose Allah, His messenger, His dīn, and the believers.
However one cannot kill nor harm kāfirs (non-believers):
"Allah does not forbid you to deal justly and kindly with those who fought not against you on account of religion and did not drive you out of your homes.
Verily, Allah loves those who deal with equity." (Quran 60:8)
"O you who believe! Stand out firmly for Allah and be just witnesses and let not the enmity and hatred of others make you avoid justice.
Be just: that is nearer to piety, and fear Allah.
Verily, Allah is Well-Acquainted with what you do." (Qur'an 5:8)
Similar concepts in Shia Islam are called Tawalla & Tabarra.