Hazrat Hakam narrates from some people of Madinah, among whom, I think, is Abu Ja'far as well, that the Messenger of Allah (peace and blessings be upon him) used to recite Surah Jumu'ah and Surah Munafiqun in the Friday prayer. Through Surah Jumu'ah, he (peace and blessings be upon him) would give glad tidings and encouragement to the believers, and through Surah Munafiqun, he (peace and blessings be upon him) would disappoint and rebuke the hypocrites.