In our mixed schools many occasions and cermonies are held accompanied by musical sections such as: School choir and suchlike. They take the students to watch a play on the occasion of what is so-called "The World Children's Day". Allah knows best what will be displayed in this play. The director forces the nannies to be present with the students in the first row, and if I think to give up teaching, he may force me to attend or to fire me from work; what should I do?
All praise be to Allah and peace be upon the Messenger of Allah, upon his family, his Companions, and those who follow him.
Dear sister, it is obligatory upon you and upon every able Muslim to forbid evil as much as he can according to the Shari`ah guidelines. Allah (may He be Exalted) says: "Let there arise out of you a group of people inviting to all that is good (Islâm), enjoining Al-Ma'rûf (i.e. Islâmic Monotheism and all that Islâm orders one to do) and forbidding Al-Munkar (polytheism and disbelief and all that Islâm has forbidden). And it is they who are the successful." [Surat Al ` Imran: 104]. Allah (Exalted be He) says: "And whosoever fears Allâh and keeps his duty to Him, He will make a way for him to get out (from every difficulty). * And He will provide him from (sources) he never could imagine. And whosoever puts his trust in Allâh, then He will suffice him. Verily, Allâh will accomplish his purpose. Indeed Allâh has set a measure for all things." [Surat Al Ma'idah: 78 - 79]. Allah (Exalted be He) says: "And it has already been revealed to you in the Book (this Qur'ân) that when you hear the Verses of Allâh 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. Surely, Allâh will collect the hypocrites and disbelievers all together in Hell." [Surat An-Nisa ': 140] Imam Muslim reported in his Sahih that the Prophet (peace be upon him) said: "Anyone of you sees an evil let him change it with his hand however if he is unable to do so, then with his tongue; and if he is unable to do so, then with his heart; and that is the weakest form of Faith."
Enjoining good and forbidding evil is a collective duty if some people do it, the rest will not be charged, but if all people leave it, all shall be sinful if they are able to do so without an excuse or fear.
Some Hadiths were reported to warn of neglecting that obligation such as the Hadith which Imam Ahmad and At-Tirmidhy reported and At-Tirmidhy graded it as authentic on the authority of Hudhayfah ibn Al Yaman (may Allah be pleased with him) who narrated that the Prophet (peace be upon him) said: "By Him in Whose Hand my life is, you either enjoin good and forbid evil, or Allah will certainly soon send His punishment to you. Then you will make supplication and it will not be accepted." Al Albany graded it as good.
Not forbidding evil despite the ability to stop it is a proof to the weakness of faith, the lack of fear of Allah, not showing mercy to the people, lack of feeling responsibility, and keenness to the world because if we give up evil forbidding, immoralities and deniable actions shall pervail.
As for the prohibition of using musical instruments and listening to them are confirmed by the consensus of scholars including Imam Al Qurtuby, Abu Tayyib At-Tabary, Ibn As-Salah, Ibn Rajab Al Hanbaly, Ibn Al Qayyim, and Ibn Hajar Al Haytamy. It is also prohibited to sit in the places where music is played because sitting there indicate approval of deniable actions, so it is not permissible for a Muslim to sit in a place where deniable actions are committed.
Therefore, you have to tell the school administration that you will not attend, however if they insist, take a leave on that day and Allah shall provide you a way out. Allah (may He be Exalted) says: "And whosoever fears Allâh and keeps his duty to Him, He will make a way for him to get out (from every difficulty). * And He will provide him from (sources) he never could imagine. And whosoever puts his trust in Allâh, then He will suffice him. Verily, Allâh will accomplish his purpose. Indeed Allâh has set a measure for all things." [Surat At-Talaq: 2-3].
Whoever leaves something for the sake of Allah, Allah will replace it with a better. Allah (Glory be to Him) says: "Whoever works righteousness (whether male or female) while he (or she) is a true believer (of Islâmic Monotheism) verily, to him We will give a good life (in this world with respect, contentment and lawful provision), and We shall pay them certainly a reward in proportion to the best of what they used to do (i.e. Paradise in the Hereafter)." [Surat An-Nahl: 97]. It was authentically reported from the Messenger of Allah (peace be upon him) that the Holy Spirit informed me that no soul shall die until it completes its appointed lifetime and accommodates its livelihood, so fear Allah and ask for sustenance moderately. Let not delayed gains push you to acquire such by disobeying Allah, for what Allah holds shall not be obtained save by obeying Him. [Reported by Abu Nu`ay in "Al Hilyah" from the Hadith of Abu Umamah and Al Albany graded it as authentic].
So, observe patience and seek the reward from Allah. No doubt that the one who seeks the Hereafter must observe patience for hardships and be keen not to sell his religion for his world. Indeed, what Allah destined for you in this worldly life will come to you, so ask for sustenance moderately. We ask Allah to grant you success and guide you.