Sunan Ibn Majah, Chapter: The Chapters on Jihad

that the Messenger of Allah (saw) said: "The horizons will be opened to you, and you will conquer a city called Qazvin. Whoever is stationed there for forty days or forty nights, will have pillars of gold in Paradise, with green chrysolite and topped by a dome of rubies. It will have seventy thousand doors, at each door will be a wife from among the wide-eyed houris.'"