I am a high-school student and at school I see some of my Muslim brothers and sisters doing things that are illegal in the religion of Islam and I am not able of telling them in a religious way. For example: one friend was wearing the hijab and took it off after 2 weeks. Some Muslim friends kiss on the cheeks when they meet (girls and boys together). I would like to have a religious way of addressing them.

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

First of all, we ask Allah to reward you for the high interest you have in respecting the prescriptions of Allah and we ask Him to help you stick to the truth. No doubt that enjoining virtue and forbidding evil are obligatory on all Muslims. Allah Says (what means): {You are the best nation produced [as an example] for mankind. You enjoin what is right and forbid what is wrong and believe in Allah.} [Quran 3:110]

The Prophet Muhammad said: “Whoever amongst you sees evil, he should change it with his hand (i.e. physically), if he is unable he should change it with his tongue (i.e. verbally) and if he is unable, he should change it with his heart (by detesting it in his heart) and that is the weakest level of faith.” [Muslim]

Your duty is to advise them and tell them to stick to virtue and to avoid evil. You should make clear to them the danger in which they are and tell them how bad it is to commit such sins. We can deduce from your question that you study in a school where there are boys and girls together. Your advice to them should be directed to the dangers of getting mixed with the other sex. The good believer should lower his gaze from looking at what Allah has forbidden. Allah Says (what means): {Tell the believing men to reduce [some] of their vision and guard their private parts. That is purer for them. Indeed, Allah is Acquainted with what they do. And tell the believing women to reduce [some] of their vision and guard their private parts and not expose their adornment except that which [necessarily] appears thereof and to wrap [a portion of] their headcovers over their chests…} [Quran 24:30-31]

You should also make clear to them the danger of looking at the other sex on the heart and on the acts of worship of the person himself. You should warn them of what they do like kissing, touching, and shaking hands with non-Mahram women and the like, as this is lawful only for the unmarriageable men. It is proven that the Prophet Muhammad said: “If one of you were to be stabbed in the head with an iron needle, it would be better for him than touching a woman whom he is not permitted to touch.” [At-Tabarani and Al-Bayhaqi]

For more benefit for mixing at schools, please refer to Fatawa 87310, 81252 and 81833.

Allah knows best.