What is the ruling on assisting the Christians in opening churches and schools in Muslim lands?

Question:
May Allah reward you, Honorable Shaykh. This questioner asks: What is the ruling on one who assists the Christians in opening churches in Muslim lands, and likewise in opening their schools where Christianity is spread?

Answer:
This is not permissible. Muslims must not allow the Christians to establish churches, nor to repair them if they fall into ruin.
As for if Muslims take control of a land that contains churches, they leave them until they collapse and cease to exist, and they are not to be rebuilt a second time. They do not allow disbelievers to build new churches in the lands of Islam, especially in the Arabian Peninsula.
The Messenger (peace and blessings be upon him) said: It is not permissible to build churches next to mosques in the Arabian Peninsula, which is the source of the message, and which contains the Sacred Precinct, the noble Ka'bah, the qiblah of Muslims, and the origin of the call. It is not permissible for two religions to remain there, ever.
This does not mean that a disbeliever cannot enter for work and return, or enter for trade and return. What is forbidden is his settling down and owning property in the lands of the Peninsula. As for entering the Peninsula for a mission or a task, or for buying and selling, and then returning, or for work for which he was hired, there is no harm in this. Yes.