A young woman is asking about working in a casino

Firstly: 

No Muslim
doubts that Allaah has forbidden alcohol and gambling, and He has described
them as major sins. Allaah says (interpretation of the meaning): 

“O you
who believe! Intoxicants (all kinds of alcoholic drinks), and gambling, and
Al‑Ansaab (stone altars for sacrifices to idols etc) and Al‑Azlaam (arrows
for seeking luck or decision) are an abomination of Shaytaan’s (Satan’s)
handiwork. So avoid (strictly all) that (abomination) in order that you may
be successful.

91. Shaytaan (Satan) wants only to excite enmity and hatred between you with
intoxicants (alcoholic drinks) and gambling, and hinder you from the
remembrance of Allaah and from As‑Salaah (the prayer). So, will you not then
abstain?”

[al-Maa’idah 5:90-91]

Secondly: 

When Allaah
forbids a thing, He also forbids helping others to do it in any way
whatsoever. Allaah says (interpretation of the meaning): 

“Help you
one another in Al‑Birr and At‑Taqwa (virtue, righteousness and piety); but
do not help one another in sin and transgression. And fear Allaah. Verily,
Allaah is Severe in punishment”

[al-Maa’idah 5:2]

The basic
principle according to the scholars of sharee’ah is that the means are
subject to the same rulings as the ends. Everything that leads to something
haraam is also haraam. 

Thirdly: 

It is not
permissible for a Muslim to be present in a place where Allaah is disobeyed,
unless that is because of necessity or he is forced to do that. He is
obliged to denounce this evil and change it and remove it; if he cannot then
he must leave that place. The basic principle is that the Muslim should shun
sinful places and keep away from them, and not help the people there to
disobey Allaah. Staying in such places goes against the command to the
Muslim to change evil wherever he sees it, and it goes against the command
to shun places of evil and sin. 

Allaah says
(interpretation of the meaning): 

“And it
has already been revealed to you in the Book (this Qur’aan) that when you
hear the Verses of Allaah being denied and mocked at, then sit not with
them, until they engage in a talk other than that; (but if you stayed with
them) certainly in that case you would be like them.”

[al-Nisa’
4:140]

al-Qurtubi
(may Allaah have mercy on him)said: “then sit not with them, until they
engage in a talk other than that” means, other than kufr. “(but if
you stayed with them) certainly in that case you would be like them”
this indicates that it is obligatory to avoid keeping company with sinners
if they openly commit evil, because the one who does not avoid them is
approving of their actions, and approving of kufr is kufr. Allaah says: “(but
if you stayed with them) certainly in that case you would be like them”
so everyone who sits in a sinful gathering and does not denounce them,
shares the burden of sin equally with them. 

He should
denounce them if they speak of sin and commit sin. If he is not able to
denounce them then he should get up and leave, so that he will not be one of
those mentioned in this verse.  

It was
narrated that ‘Umar ibn ‘Abd al-‘Azeez (may Allaah be pleased with him)
caught some people who were drinking alcohol, and it was said to him that
one of those who were present was fasting. He had him beaten in order to
discipline him, and he recited this verse: “certainly in that case you
would be like them” i.e., approving of sin is also sin. 

End quote
from Tafseer al-Qurtubi (5/418) 

Shaykh Ibn
Baaz (may Allaah have mercy on him) said: 

Denouncing
sin in one’s heart is obligatory for every one, which means hating and
despising the evil, and separating from those who commit sin if one is
unable to denounce it with one’s hand or tongue (i.e., by taking action or
speaking out). 

Al-Durar
al-Saniyyah fi’l-Ajwabah al-Najdiyyah (16/142) 

Moreover
there is the fear that the one who works in these places will become weak in
faith, and may lose all sense of gheerah (protective jealousy), and the
shaytaan may tempt him to sin. Allaah says (interpretation of the meaning): 

“O you
who believe! Follow not the footsteps of Shaytaan (Satan). And whosoever
follows the footsteps of Shaytaan (Satan), then, verily, he commands
Al‑Fahshaa’ [i.e. to commit indecency (illegal sexual intercourse)], and
Al‑Munkar [disbelief and polytheism (i.e. to do evil and wicked deeds; and
to speak or to do what is forbidden in Islam)]”

[al-Noor
24:21]

Fourthly: 

Based on the
above, it is not permissible for a Muslim to work in these casinos, because
then he will helping others to disobey Allaah and approving of sin, or he
will come under the ruling of one who approves of sin. That includes all
those who work in these casinos, it includes those who play with the
customers, or teach them, guard them, serve them, receive them and other
jobs. The Muslim should not be deceived by the salary he gets, for on the
Day of Resurrection he will be asked about his wealth, from where he
acquired it and on what he spent it. 

The most
precious thing that a Muslim has is his religious commitment, so he must
guard it and not be one of those who sold their religion for a trifling
price of worldly gain which will soon pass away. 

This is the
ruling: it is haraam to work in these places; and in your case, it is even
more haraam. Do you know why? 

Because you
are a woman, and you are less able to put up with things and resist than a
man is, and the evildoers’ hopes of corrupting you will be stronger. How can
a girl of your age be sure that she will be safe if she is among those
deviants in those casinos with their alcohol, drunkenness and desires? 

We hope that
you will submit to sharee’ah and reason, and you will not go anywhere near
those places, so as to protect yourself and the most precious thing that you
possess. 

Remember the
words of Allaah (interpretation of the meaning):

“And
whosoever fears Allaah and keeps his duty to Him, He will make a way for him
to get out (from every difficulty).

3. And He
will provide him from (sources) he never could imagine. And whosoever puts
his trust in Allaah, then He will suffice him. Verily, Allaah will
accomplish his purpose. Indeed Allaah has set a measure for all things”

[al-Talaaq 65:2-3]

And remember
the words of the Prophet (peace and blessings of Allaah be upon him):
“Whoever gives up something for the sake of Allaah, Allaah will compensate
him with something better than it.” Classed as saheeh by al-Albaani. Do not
forget that no soul will die until it has received its provision in full,
sooner or later.

We ask Allaah to help you to forego this job willingly, and to compensate
you with something better than it, and to bestow His bounty upon you, and to
make us and you independent of means through halaal ways so that we have no
need of that which is haraam. 

And Allaah
knows best.