Musnad Abu Ya'la al-Mawsili 108:186

Muhammad ibn al-Sabbah narrated to us, Ismail ibn Zakariyya narrated to us, from al-A'mash, from Abu Sufyan, from Jabir, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "There is nothing between the servant and his abandoning of faith except his abandoning of the prayer."