I know somebody's secret and I am eager to tell it to others, but I'm reluctant. I don't know the Islamic ruling about it. The person begged me not to tell her secrets to other and I asked for some favors in return (blackmail). My other question is can I accept money from such kind of blackmailing, meaning is this money Halal for me? The person whose secret I know is a Muslim but does not say her prayers, only occasionally, meaning she could be called Kafir for not saying prayers.
Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
It is not good character for a Muslim to pursue faults of a Muslim or to unveil them. It is also forbidden to threaten or blackmail one on his shortcomings. The Prophet (Sallallahu Alaihi wa Sallam) said: "If one covers a Muslim, Allah will cover him the Day of Judgment" [Reported by Imams al-Bukhari and Muslim ].
The Prophet (Sallallahu Alaihi wa Sallam) also said: "O people who declare Islam by tongue and faith has not got into their hearts; do not harm Muslims, do not mock at them and do not pursue their lapses. Whoever follows the lapses of Muslims Allah will follow his lapses; and when Allah follows the lapses of a person He will uncover his faults even in his interior house" [ al-Tirmizi ].
Covering means covering the faults of a person who makes repentance; otherwise, the one who continues to commit sin should be stopped from doing it. The woman who does not pray should be advised and informed about the ruling of the one who abandons prayers.
However, you are not allowed to take any money for the saying of the Prophet (Sallallahu Alaihi wa Sallam): "The property of a Muslim man is not Halal except if he allows it willingly" [ Abu Dawood ].
Therefore, fear Allah, avoid His punishment and leave this woman without harm.
Allah knows best.
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