Wikipedia
Al-Kafirun
Sūrat al-Kāfirūn (, "The Unbelievers") is the name of the 109th Sura (chapter) of the Qur'an.
Like many of the shorter Suras, the Sura of the Unbelievers takes the form of an invocation, telling the reader something they must ask for or say aloud. Here, the passage asks one to keep in mind the separation between belief and unbelief both in the past and the present, ending with the often cited line "To you your religion, and to me mine".
It was revealed in Mecca when the Muslims were persecuted by the polytheists of Mecca.