Islamic ruling on placing Islamic projects in the hands of non-Muslims

It is not permissible to hand over Islamic works such as those mentioned
to kaafir workers, because they cannot be trusted and we cannot be sure
that they are sincere. Allaah says (interpretation of the meaning); 

“Indeed there has been an excellent
example for you in Ibraaheem (Abraham) and those with him, when they
said to their people: ‘Verily, we are free from you and whatever you
worship besides Allaah, we have rejected you, and there has started
between us and you, hostility and hatred for ever until you believe
in Allaah Alone’” [al-Mumtahanah 60:4]

“The believers,
men and women, are Awliyaa’ (helpers, supporters, friends, protectors)
of one another” [al-Tawbah 9:71]

“And
those who disbelieve are allies of one another, (and) if you (Muslims
of the whole world collectively) do not do so [i.e. become allies, as
one united block under one Khaleefah (a chief Muslim ruler for the whole
Muslim world) to make victorious Allaah’s religion of Islâmic Monotheism],
there will be Fitnah (wars, battles, polytheism) and oppression on the
earth, and a great mischief and corruption (appearance of polytheism)”

[al-Anfaal 8:73]

The Council of Major Scholars in the Kingdom of Saudi Arabia
has issued a statement that it is forbidden to delegate the building
of mosques to non-Muslims, because of the evidence (daleel) and reasons
referred to above.