This is a very evil concept. It means love those who are with us (Muslims) and hate those who are not (non-Muslims), or more accurately, allegiance and association with the people of Islam and Emaan (faith) and disassociation and enmity with the people of falsehood and disbelief in Islam (i.e you filthy infidels)
In the following hadith, we can see what is meant by having 'faith' islamically speaking:
"Umar bin Khattab (ra) narrated in the Hadith of Jibreel, that Muhammad (saw) said,
O Muhammad, tell me about Emaan (faith), he (Muhammad) said, “It is to believe in Allah, His angels, His books, His Messengers, and the Last Day, and to believe in divine destiny, both the good and the evil thereof.”
Ok. Let us see what his books and messengers tell us about how we are to interact with our non- believing earthly co-inhabitants shall we?
"Qur'an al-Fath (victory/conquest) 48.29 Muhammad is the messenger of Allah; and those who are with him are hard against Unbelievers, (but) compassionate and merciful amongst each other. Thou wilt see them bow and prostrate themselves (in prayer), seeking Grace from Allah and (His) Good Pleasure. On their faces are their marks, (being) the traces of their prostration. This is their similitude in the Taurat; and their similitude in the Gospel is: like a seed which sends forth its blade, then makes it strong; it then becomes thick, and it stands on its own stem, (filling) the sowers with wonder and delight. As a result, it fills the Unbelievers with rage at them. Allah has promised those among them who believe and do righteous deeds forgiveness, and a great Reward."
Herein lies the concept of Al-walaa wal baraa . It is divided into two aspects: al-Hubb (love) and al-Bughoud (hatred); both of which have to be done purely for the sake of Allah. Al-Hubb means to love for the sake of Allah, otherwise known as Muwalaat. Remember this word, it is key to understanding how the Muslim mind is set and gives us an insight into the cultish behavioral patterns often exhibited by Muslims.
Al-Muwalaat is to accompany, to love, to support, to ally, to help, to elevate, to respect and to befriend, all of which must be done for the sake of Allah in the manner that He has commanded.
Al-Bughoud on the other hand is to have hatred for the sake of Allah also known as al-Muadaat, which is the complete opposite to muwalaat. Hence the requirement upon the believers is to have muwalaat with the Muslims and to have muadaat against the kuffar, to love Allah, the Messenger and the Muslims and have hatred for the kuffar, to love all that Allah commands Muslims to love and show walaa towards them, to have no rejection or animosity towards any of the commands of Allah and to hate all that Allah hates together with those who hate Allah and the believers.
"O you who believe, do not take the kafireen as awliyaa' (friends/helpers) instead of the Believers, do you wish to take Allah as a proof against you?" [Qur'an an-nisa 4: 144]
It must be clear in the minds of the Muslims that to love, support, ally, accompany, help, respect, elevate and befriend are attributes that should be directed solely to the Muslims and in no way towards the kuffar as Allah states in the Qur'an;
"Let not the believers Take for friends or helpers Unbelievers rather than believers: if any do that, in nothing will there be help from Allah. except by way of precaution, that ye may Guard yourselves from them. But Allah cautions you (To remember) Himself; for the final goal is to Allah." [Qur'an al-imran 3: 28].
Al-Muwalaat is obligatory between the believers as Allah described the Muslims as a single brotherhood distinguishing them from the disbelievers. Allah says:
"The Believers are but a single Brotherhood: So make peace and reconciliation between your two (contending) brothers; and fear Allah, that ye may receive Mercy." [Qur'an al-Hujurat 49: 10]