Missionary Groups Adopting Muslim Orphans

It
is not permissible to hand over Muslim orphans to the non-Muslims, Christians or others, because of the great danger that this poses to the orphans,
and because they will not be given an Islamic upbringing. They (orphans)
are a trust (amaanah) for which the Muslims are responsible, so it is
not permissible to place them under the guardianship of anyone else.
Allaah says (interpretation of the meaning):

“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 Islamic 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]