My religion told me about your religion! The student of religion is very often discouraged and deterred by the discovery that all religion spends so much time and effort commenting upon, and criticizing the religions of others.
For the good Muslim, it is God who speaks in the Qur’an; it is God who writes the poetry of the Qur’an, and in this poem God mentions the Jewish people and the Christians by name. To be more precise, God devotes more than twenty per cent of the Qur’an to talking about Judaism, Christianity and other religions.
God discusses the failings, or otherwise, of the Sabeans, possibly the Mandaeans, and of numerous ancient religions of various Arabic tribes.