[And their prayer at the House was nothing but whistling and clapping]. Al-Hasan said: The whistling is the blowing of breath, and the clapping is the striking of hands together; he says: They used to do that instead of prayer.
Mujahid said: They used to do it to confuse the Prophet (peace and blessings of Allah be upon him) in his prayer.
[So taste the punishment] meaning: the killing by the sword before the punishment of the Hereafter [for what you used to disbelieve].
Surat al-Anfal from verse (36) to verse (40).
﴿وَمَا كَانَ صَلاتُهُمْ عِنْدَ الْبَيْتِ إِلَّا مكاءً وتصدية﴾ قَالَ الْحَسَنُ: الْمُكَاءُ: الصَّفِيرُ، وَالتَّصْدِيَةُ: التَّصْفِيقُ؛ يَقُولُ: يَفْعَلُونَ ذَلِكَ مَكَانَ الصَّلاةِ.
قَالَ مُجَاهِدٌ: وَكَانُوا يَفْعَلُونَهُ ليخلطوا عَلَى النَّبِيِّ ﷺ الصَّلَاة.
﴿فَذُوقُوا الْعَذَاب﴾ يَعْنِي: الْقَتْلَ بِالسَّيْفِ قَبْلَ عَذَابِ الْآخِرَة ﴿بِمَا كُنْتُم تكفرون﴾.
سُورَة الْأَنْفَال من الْآيَة (٣٦) إِلَى الْآيَة (٤٠).