al-Walaa wal-Baraa according to the Creed of the Salaf

Question: What is the meaning of al-Walaa' wal-Baraa'

Answer:
Loyalty and disavowal means loving the believers and being loyal to them, hating the unbelievers, being their ennemy and disavowing them and their religion.

That is loyalty and disavowal like Allah said in sourat al-moumta7ana:

There is for you an excellent example (to follow) in Abraham, and those with him, when they said to their people: we are clear of you and whatever ye worship besides Allah: we have rejected you, and there has arisen, between us and you, enmity and hate forever, unless ye believe in Allah and Him alone. (Quran 60:4)

Hating them and being their enemy does not mean oppressing them or being aggressive towards them if they are not combatants; it means hating them and being their enemy in your heart, not having them as your friends. However, do not hurt them, or hit them or oppress them. If they greet you, you should return their greeting, advise them to do good because Allah said:
And dispute ye not with the people of the book, except with means better (than disputation). (Quran 29:46)

The people of the book are the Jews and the Christians and other non-Muslims to whom you promised safety. But those of them who oppress others, must be punished.

A believer can dispute with them with better means (see the previously stated verse) because Allah said: Invite (all) to the way of thy Lord with wisdom and beautiful preaching and argue with them in ways that are best and most gracious. (Quran 16:125)

So a believer cannot aggress or oppress the non-believers, even though he hates them for the sake of Allah, he can invite them to Islam (i.e give da'wah to them) and teach them and guide them to the truth, lest Allah guides them with His reasons to the correct path (i.e ISlam).

And it is permissible to give them charity because Allah said: Allah forbids you not, with regards to those who fight you not for your faith nor drive you out of your homes, from dealing kindly and justly with them: for Allah loves those who are just. (Quran 60:8)

As was proven in the two Sahihs (i.e Bukhari and Muslim), the Prophet, Sallalahu aleyhi wa sallam, ordered Asmaa bint Abi Bakr (Radiallahu anha) to maintain her relation with her mother who was a disbeliever after the truce that was agreed between the Prophet (Sallalahu aleyhi wa sallam) and the people of Mecca.

Source: Majmoo' al-Fatawaa