It is narrated from Hazrat Imran bin Husain (may Allah be pleased with him) that on the occasion of the conquest of Makkah, the Prophet (peace and blessings be upon him) stayed for eighteen days. I was also with him, but he continued to lead the people in two rak'ahs (shortened prayer), and he would tell the people of the city to complete their prayer because we are travelers.
Hadith Referenceمسند احمد / أول مسند البصريين / 19878
Hadith Gradingحکم دارالسلام:صحيح لغيره دون قوله: صلوا أربعا فإنا سفر ، وهذا إسناد ضعيف من أجل على بن زيد