The Heavenly Decree is the English translation of Asmani Faisala by Hazrat Mirza Ghulam Ahmad, the Promised Messiah and Mahdi(as) and the Founder of Ahmadiyya Muslim Community. It is addressed to his contemporary ulema, specially Miyan Nadhir Husain Dehlawi and Maulawi Muhammad Husain of Batala who had issued a fatwa of heresy against the Promised Messiah(as) and declared him a non-Muslim, because he (the Promised Messiah(as)) had claimed that Jesus Christ had died a natural death and the second coming of Masih ibni Maryam (Jesus Christ) is fulfilled by the advent of Hazrat Mirza Ghulam Ahmad(as). Because (by the time the book was written) the ulema had refused to debate this issue with the Promised Messiah, he invited them, in this book, to a spiritual contest in which the question whether someone is a Muslim or not would be settled by Allah himself on the basis of four criteria of a true believer as laid down by Him in the Holy Quran. He also spelled out the modus operandi of this contest and fixed the period of time frame within which this contest would be decreed by Allah. He declared that God would not desert him and would help him and would grant him victory.
