"Thus while he began the Islamization of Pakistan in earnest, Zia al-Haq took time to write what, at first sight, might seem an extraordinary endorsement of The Qur’anic Concept of War (1979), by Brigadier S.K. Malik... It is constantly quoted and referred to by modern jihādists. However, given the President’s Islamization programme for Pakistan and the fact that jihād is the quintessential Islamic duty, Zai al-Haq’s stamp of approval of Brigadier Malik’s treatise makes perfect sense... Brigadier Malik makes it clear that jihād is essential for the spread of Islam, and it is a duty incumbent on all Muslims until Islam covers the whole surface of the earth."