Musnad Abu Ya'la al-Mawsili 148:10

Abu Ali al-Hasan narrated to us, Yunus narrated to us, Layth narrated to us, from Yazid, from Sa’d ibn Sinan, from Anas, from the Prophet (peace be upon him), that he used to say: "Before the Hour, there will be tribulations like pieces of the dark night. A man will wake up as a believer and reach the evening as a disbeliever, and he will wake up as a disbeliever and reach the evening as a believer. A people will sell their religion for a small amount of worldly goods."