From Karen Armstrong’s A History of God: The 4,000-Year Quest of Judaism, Christianity and Islam:

Politics is not extrinsic to a Muslim’s personal religious life, as in Christianity, which mistrusts mundane success.  Muslims regard themselves as committed to implemented a just society in accord with God’s will.  The ummah has sacramental importance, as a “sign” that God has blessed this endeavor to redeem humanity from oppression and injustice; its political health holds much the same place in a Muslim’s spirituality as a particular theological option (Catholic, Protestant, Methodist, Baptist) in the life of a Christian.  If Christians find the Muslims’ regard for politics strange, they should reflect that their passion for abstruse theological debate seems equally bizarre to Jews and Muslims.