Sahih al-Bukhari 2288
Sahih al-Bukhari · Book 38: Transferance of a Debt from One Person to Another (Al-Hawaala) · If somebody's debt are transferred to a rich debtor
Narrated Abu Huraira:
حَدَّثَنَا مُحَمَّدُ بْنُ يُوسُفَ ، حَدَّثَنَا سُفْيَانُ ، عَنِ ابْنِ ذَكْوَانَ ، عَنِ الأَعْرَجِ ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " مَطْلُ الْغَنِيِّ ظُلْمٌ، وَمَنْ أُتْبِعَ عَلَى مَلِيٍّ فَلْيَتَّبِعْ " .
The Prophet (ﷺ) said, "Procrastination (delay) in paying debts by a wealthy person is injustice. So, if your debt is transferred from your debtor to a rich debtor, you should agree."