Sheikh `Atiyyah Saqr, former head of Al-Azhar Fatwa Committee, states the following: “Almighty Allah says: “And their worship at the (holy) House is naught but whistling and hand clapping.” (Al-Anfal: 35)
The Arabic word Muka’ means whistling, and the word Tasdiyah means clapping hands. This is the explanation of Ibn `Umar, As-Suddy, Mujahid. Commenting on this verse, Ibn `Abbas said that the Quraysh used to go naked around the Ka`bah, whistling and clapping their hands. They thought that to be an act of worship.

Hence, it is clear that one cannot draw near to Allah through whistling and clapping hands, viewing that as an act of worship. In his commentary on the Qur’an, Imam Al-Qurtubi resisted the conduct of some ignorant Sufis who think that dancing and clapping hands are acts of worship. In this regard, he said: “It is a detestable act from which rational people should refrain. Whoever does this is imitating the polytheists who used to circumambulate around the Ka`bah, whistling and clapping their hands.”

However, if clapping hands are express one’s admiration for a respectable person. That is to say, clapping hands is a custom or social norm of showing respect and admiration, and in this sense there is nothing wrong in it from the Shari`ah’s viewpoint. Nevertheless, it is not commendable for Muslims to clap their hands in ceremonies that are held in mosques, not to be like the pre-Islamic polytheists who used to do so in the Sacred Precinct. At mosques one can, however, express admiration by celebrating Allah’s Greatness, saying Allahu Akbar or any other words that opt for the sacredness of the mosque. It was reported with a weak chain of transmission that the Prophet, peace and blessings be upon him, showed his admiration for some lines of verse An-Nabighah recited by saying: “How well you have spoken! O, Abu Layla.” The same did the Prophet when his uncle Al-`Abbas praised him in a poem. [Source: Al-`Iraqi’s commentary on Al-Ihya’– the chapter on ‘manners of listening’]”