Assalam Alaykum. Is whistling haram?
walekummasalam wa rehmatullah :) The ruling of whistling will depend on what reason it is used for. If it is done to cause disturbance and inconvenience to others, then it will be impermissible. Almighty Allah describing the action of the disbeliever in the Holy Qur’an says:
وَمَا كَانَ صَلَاتُهُمْ عِنْدَ الْبَيْتِ إِلَّا مُكَاءً وَتَصْدِيَةً فَذُوقُوا الْعَذَابَ بِمَا كُنْتُمْ تَكْفُرُونَ
And their prayer near the House was not more than whistling and clapping. So taste the punishment, because you used to disbelieve. (8/35)
In the commentary of this verse, Mujahid (Rahimahu Allah) says, “They (the enemies) did this to disturb the prayer of the Prophet (Sallalahu ‘Alaihi Wasallam).” (Ibn Kathir)
To cause harm and disturbance to others is unlawful in Shari’a. Almighty Allah says in the Qur’an:
والَّذِينَ يُؤْذُونَ المُؤْمِنِينَ والمُؤْمِنَاتِ بِغَيْرِ مَا اكْتَسَبُوا فَقَدِ احْتَمَلُوا بُهْتَاناً وَإثْماً مُبِيناً – الأحزاب 58
As for those who hurt believing men and believing women without their having done anything (wrong), they shall bear the burden of slander and a manifest sin. (Al-Ahzab -58)
The Prophet of Allah (Sallallahu 'Alayhi Wasallam), describing the qualities of a believer, said:
المسلم من سلم المسلمون من لسانه ويده – متفق عليه
A (true) Muslim is he from whose tongue and hand other Muslims are free. (Al-Bukhari & Muslim)
The ruling of whistling will depend on the reason and how it is used. If it is used for example by a lost person to identify his whereabouts, then it is permissible. If it is used in the context of music, it will be prohibited.
And Allah knows best !