Praise
be to Allaah.
If you are sent to wage war against the Muslims, then
it is not permissible for you to take part at all. Helping the kaafirs
against the Muslims is a form of major kufr which puts one beyond the
pale of Islam. Allaah says concerning one who supports the mushrikeen
(interpretation of the meaning):
“And if any amongst you takes them (as Awliyaa’, i.e.,
friends), then surely, he is one of them”[al-Maa’idah 5:51]
With regard to how
you may get out of this situation, and what excuse you can give to get
out of this dilemma if it happens, we ask Allaah to help you, and we
suggest that you consult some Muslims who have relevant knowledge or
experience.
We want to emphasize to you the necessity of finding
other employment and of leaving service in the army of the kaafirs,
because that implies helping them, strengthening them and increasing
the numbers of their fighters and supporters – unless your work can
bring some benefits to the Muslims, such as giving information and secrets
of the kaafirs to the Muslims so as to help the Muslims, or if your
work is purely da’wah, such as giving khutbahs and leading prayers for
the Muslims in the kaafir army whilst also advising them to avoid any
work that will strengthen the kaafirs. We ask Allaah to keep you safe
from temptation and to give you a good end in this world and in the
Hereafter.