Surah 4. An-Nisaa', Ayah 126

Usually secrecy is for evil ends, or from questionable motives, or because the person seeking secrecy is ashamed of himself and knows that if his acts or motives became known, he would make himself odious. Islam therefore disapproves of secrecy and loves and enjoins openness in all consultations and doings. But there are three things in which secrecy is permissible, and indeed laudable, provided the motive be purely unselfish, to earn "the good pleasure of Allah": (1) if you are doing a deed of charity or beneficence, whether in giving material things or in helping in moral, intellectual, or spiritual matters; here publicity may not be agreeable to the recipient of your beneficence, and you have to think of his feelings; (2) where an unpleasant act of justice or correction has to be done; this should be done, but there is no virtue in publishing it abroad and causing humiliation to some parties or adding to their humiliation by publicity; (3) where there is a delicate question of conciliating parties to a quarrel; they may be very touchy about publicity but quite amenable to the influence of a man acting in private.