﴿ وَمَا كَانَ صَلَاتُهُمْ عِندَ ٱلْبَيْتِ إِلَّا مُكَآءًۭ وَتَصْدِيَةًۭ ۚ فَذُوقُوا۟ ٱلْعَذَابَ بِمَا كُنتُمْ تَكْفُرُونَ ﴾

“and their prayers before the Temple are nothing but whistling and clapping of hands. Taste then, [O unbelievers,] this chastisement as an outcome of your persistent denial of the truth!”

(And their worship at the (holy) House is naught but whistling) like the whistling of a bird (and hand clapping. Therefore (it is said unto them): Taste of the doom) on the Day of Badr (because you disbelieve) in Muhammad (pbuh) and the Qur'an.