Sunan Abu Dawud
3342
Daif+3

Narrated AbuMusa al-Ash'ari: The Prophet (ﷺ) said: After the grave sins which Allah has prohibited the greatest sin is that a man dies while he has debt due from him and does not leave anything to pay it off, and meets Him with it

DaifAl-Albani
DaifMuhammad Muhyi Al-Din Abdul Hamid