Islamic concept of Al-Taqiyah to infiltrate and destroy kafir countries

According to Al-Taqiyah, Muslims were granted the Shar’iyee right (legitimacy) to infiltrate the Dar el-Harb (war zone), infiltrate the enemy’s cities and forums and plant the seeds of discord and sedition. These agents were acting on behalf of the Muslim authority at war, and therefore were not considered as lying against or denouncing the tenants of Islam.

They were "legitimate" mujahedeen, whose mission was to undermine the enemy’s resistance and level of mobilization. One of their major objectives was to cause a split among the enemy’s camp while downplaying the issues related to Islam ("Oh, I am not religious." "Oh, that is not Islam, you are mistaken, there is so much misinformation." "Oh, it is in the interpretation." "Brother, Islam is all about peace and love and music just like in the 60s.")...
These are examples of a practice known as taqiyya, which essentially means to lie for the sake of Islam. The intention is to deceive unbelievers about Islam, for the explicit purpose of assuaging doubts and concerns about Islam, and encouraging conversion. Taqiyya underlies the whole gamut of Muslim propaganda which is disseminated in the West, from the claim that Islam promotes equal rights for women, to the attempts at inflating the perceived number of Muslims...

Taqiyya goes beyond mere lying for propaganda purposes. The word comes from a root meaning "to guard against, to keep (oneself)". It thus also includes dissimulation by the Muslim to give the appearance of not being religious, so as not to arouse suspicion. In this vein, a Muslim, if necessary, may eat pork, drink alcohol, and even verbally deny the Islamic faith, as long as he does not "mean it in his heart". If the end result of the lie is perceived by the Muslim to be good for Islam or useful to bringing someone to "submission" to Allah, then the lie can be sanctioned through taqiyya. As al-Tabbarah writes,

"Lying is not always bad, to be sure; there are times when telling a lie is more profitable and better for the general welfare, and for the settlement of conciliation among people, than telling the truth. To this effect, the Prophet says: ’He is not a false person who (through lies) settles conciliation among people, supports good or says what is good."28
The taqiyya concept is also found 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." (Surah 3:28)