Her younger sister blackmails her and complains about her to her parents
19-10-2009 | IslamWeb
Question:
Assalamualikum what is the ruling on the person who spy on others ? my younger sister feels that its an obligation on her to know what i am doing, no matter what ever it is if i do the same she does not like that, she like to search about me and then either blackmail me or complain to parents ? i did not any major sin even though Alhamduliah i repented and gave up but still she wants to interfere .....saying i do not trust u ? u can do anyting? i am not a small girl. Alhamdulillah i am blessed with little islamic knowledge and know do's and dont's. what i do is between me and Allah. i hate her interferince in my life. iwant her to mind her own work and keep away from my matters? pls advice very soon. i will show her this fatwa. inshallah. jazakAllahukhair.
Answer:
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, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Spying on others and having bad thoughts about them are grave sins that texts of the Quran and Sunnah prohibited. This was previously clarified in Fatwa 83404. If what you mentioned about your sister is true, that she mistrusts you and tries to find out your faults, she is wrong and has done an evil act. We remind her to fear Allaah The Almighty and inform her that the Muslim is in principle free of sins, so it is not permissible to accuse him of without evidence.
However, supposing that a Muslim saw someone doing an evil act, it would be obligatory for him to cover him (i.e. his evil act) and advise him. It would be impermissible to disclose his evil act to others unless there is a considerable benefit involved. For example, a person may stop an evil act by threatening him to tell someone who can deter him, such as his guardian. Nevertheless, this should be done only to the extent needed.
On the other hand, we say to this sister: do you not fear that Allaah The Almighty would do the same thing to you and allow others to find out your faults and disclose them? Ibn ‘Umar 
reported that the Prophet, sallallaahu ‘alayhi wa sallam, said: "O people who professed faith outwardly and faith did not enter their hearts! Do not harm Muslims, or scoff at them or seek out their faults. The person who seeks out the faults of his Muslim brother, Allaah The Almighty will seek out his faults; and if Allaah The Almighty seeks out the faults of anyone, He will disgrace him even if he hides himself in his saddlebag." [At-Tirmithi]
Finally, we advise you to exert your best effort in worshiping Allaah, befriend righteous women and avoid suspicious places.
Allaah Knows best.