Musnad Abu Ya'la al-Mawsili 108:233

Narrated to us Ishaq ibn Abi Isra'il, narrated to us Yahya ibn Sulaym, from Ibn Khuthaym, from Abd al-Rahman ibn Sabit, that Jabir ibn Abdullah narrated to him, [who] heard the Messenger of Allah (may Allah bless him and grant him peace) saying to Ka'b ibn Ujrah: "O Ka'b ibn Ujrah, the prayer is a means of nearness, fasting is a shield, and charity extinguishes sin just as water extinguishes fire. O Ka'b ibn Ujrah, people are of two types in their morning: one who sells his soul, thereby destroying his neck, and one who buys his soul, thereby freeing his neck."