Allah T'ala (God, the Most High) says in the Holy Quran:
022.039 To those against whom war is made, permission is given (to fight), because they are wronged;- and verily, God is most powerful for their aid;-
022.040 (They are) those who have been expelled from their homes in defiance of right,- (for no cause) except that they say, "our Lord is God".
Did not God check one set of people by means of another, there would surely have been pulled down monasteries, churches, synagogues, and mosques, in which the name of God is commemorated in abundant measure. God will certainly aid those who aid his (cause);- for verily God is full of Strength, Exalted in Might, (able to enforce His Will).
Safeguarding monasteries, churches, synagogues, and mosques is an Islamic cause. Those who destroy houses of worship or kill worshippers commit un-Islamic and un-Godly acts.
During the life of Prophet Muhammad, the Jews in Madina had a synagogue and an educational institute, Bait-Al-Midras. The Prophet preserved the institute and gave protection to the Jews.
The Prophet respected the autonomy of the Christian churches. The nomination and the appointment of bishops and priests was left to the Christian community itself.
The Prophet sent a message to the monks of Saint Catherine in Mount Sinai:
"This is a message written by Muhammad ibn Abdullah, as a covenant to those who adopt Christianity, far and near, we are behind them. Verily, I defend them by myself, the servants, the helpers, and my followers, because Christians are my citizens; and by Allah! I hold out against anything that displeases them. No compulsion is to be on them. Neither are their judges to be changed from their jobs, nor their monks from their monasteries. No one is to destroy a house of their religion, to damage it, or to carry anything from it to the Muslims' houses. Should anyone take any of these, he would spoil God's covenant and disobey His Prophet. Verily, they (Christians) are my allies and have my secure charter against all that they hate. No one is to force them to travel or to oblige them to fight. The Muslims are to fight for them. If a female Christian is married to a Muslim, this is not to take place without her own wish. She is not to be prevented from going to her church to pray. Their churches are to be respected. They are neither to be prevented from repairing them nor the sacredness of their covenants. No one of the nation is to disobey this covenant till the Day of Judgment and the end of the world."
compiled by Ishaq Zahid