Monasteries,Churhces and Synagogues must be Respected

A Muslim must respect and protect the holy places where the People of the Book worship God, and protect them. For Muslims, these places are precious because in these places, people, whether Jews or Christians, remember God. In the Qur'an, the places of worship of the People of the Book, ie. monasteries, churches and synagogues, are mentioned as places of worship protected by God.

…if God had not driven some people back by means of others, monasteries, churches, synagogues and mosques, where God's name is mentioned much, would have been pulled down and destroyed. God will certainly help those who help Him—God is All-Strong, Almighty. (Qur'an, 22:40)

As a manifestation of his loyalty to God's commands, the Prophet Muhammad (pbuh) was most careful not to destroy the holy places of the People of the Book. Such destruction means, in the first place, opposing God's commands. This aside, it means preventing people who have faith in God worshipping Him. Indeed, the Prophet Muhammad (pbuh) promised the Christians, who were the other party to a peace agreement he made, that their churches would not be destroyed and that they would never be harmed. The tax (Jizya) agreements he made with Christians also guaranteed the safety of churches.
The first agreement made after the death of the Prophet (pbuh) that guaranteed the protection of the temples was a tax agreement Khalid bin al-Waleed signed with the leader of the city of Anat. Ibn Ishaq stated that those agreements made by Khalid bin al-Waleed were also approved by Abu Bakr and the three caliphs following him.16 This aside, Abu Bakr offered the same guarantees that had been offered to the people of Najran by the Prophet Muhammad (pbuh).
The Islamic societies that abided by Islamic morality after the death of the Prophet (pbuh) also paid special attention to this issue. Muslim leaders who adhered to the Qur'an and the Sunnah (the sayings and doings of the Prophet Muhammad (pbuh)) respected the places of worship of non-Muslims in conquered countries and showed great tolerance to the clergy. Christians who lived under Muslim rule for centuries never rebelled for religious reasons. This, there is no doubt, is the result of the just and tolerant attitudes of Muslim leaders in compliance with Qur'anic rules.