Musnad Ahmad 788:11

'Abdullah ibn Yazid narrated to us, Sa'id ibn Abi Ayyub narrated to us, he said: I heard a man from Quraysh who was called Abu 'Abdullah, who used to sit with Ja'far ibn Rabi'ah, he said: I heard Abu Burdah al-Ash'ari narrating from his father, from the Prophet, may Allah bless him and grant him peace, who said: "Indeed, the greatest of sins before Allah, the Almighty and Majestic, for a servant to meet Him with—after the major sins which He has forbidden—is that a man dies while he has a debt upon him, and he does not leave behind [the means for] its repayment."