Principle number 18 of Basic Elements of Islam: The Quran uses the carrot and stick to reinforce behavior. Throughout the book are vivid descriptions of hell, where sinners and non-Muslims have to drink boiling, stinking water, are thrown face down into a raging fire, and have to be there for eternity, suffering endless torments in agony. Read more about this.
There are also vivid descriptions of Paradise. In Paradise, believers wear green silk robes and recline on plush couches. Trees shade them, fruit dangles nearby. Believers have tasty food and refreshing drinks served to them in silver goblets.
But to have a chance of reaching Paradise, they must be devout Muslims. To guarantee it, they must die in jihad (for men) or make sure their husbands are always happy with them (for women).