assalam o alaikum i am a doctor and i live in pakistan my family is not that religious. we are basically partly practicing muslims. recently my parents have allowed my youger sisters to have cell phones and they have been caught having boyfriends. my mom scolded and beat them but they still got to keep their phones despite my protest. now they are very sneaky when they use their phones they hide it from me they delete their texts and lock their phones. this makes me suspicious about them. i have talked to mom but to no avail. i dont know what to do about this i feel sp angry with them all the time i just want to beat them when i see them on their phones. my mom doesnt pay any heed to what i tell her what should i do should i spy on them? i tried doing that and it only made me feel more miserable. i am not able to show kindness to them because of this i dont even like to see their faces. i am really confused.. please respond to my query asap Allah will reward you inshaa Allah. Jazakallah khair

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

A Muslim is prohibited from spying on Muslims and having bad assumptions about them, even if this is on the grounds of forbidding evil; Allaah says (what means): {O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin. And do not spy ...} [Quran 49:12]

Spying on people in order to forbid evil may lead to corrupting them, as stated in the Hadeeth: “…if you search for the faults of the people, you will corrupt them, or you will nearly corrupt them.” [Abu Daawood - Ibn Hibbaan graded it Saheeh (sound)]

So, you should avoid spying on your sisters and being suspicious about them. Also, you are not allowed to beat them; as the only one who  is allowed to beat them is the one who is given the authority to discipline them. Rather, you should advise them and admonish them in a good and gentle manner, and supplicate Allaah to guide them and keep them away from evil and immorality.

For more benefit, kindly refer to Fatwa 16126.

Allaah Knows best.