Sayyiduna Imran bin Husayn (may Allah be pleased with him) said: When the Messenger of Allah (peace and blessings be upon him) conquered Makkah, he stayed there for eighteen nights, leading the people of Makkah in two rak'ahs in every prayer except Maghrib, and then he would say: "O people of Makkah, complete your prayers, for we are a people on a journey."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 15608