The prohibition of a rich man delaying repayment. The validity of Hawalah (Transferal of Debts) and it is recommended to accept transferal of a debt if it is transferred to a rich man
حَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، . أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ " مَطْلُ الْغَنِيِّ ظُلْمٌ وَإِذَا أُتْبِعَ أَحَدُكُمْ عَلَى مَلِيءٍ فَلْيَتْبَعْ " .
Abu Huraira (Allah be pleased with him) reported Allah's Messenger (ﷺ) as saying: Delay (in the payment of debt) on the part of a rich man is injustice, and when one of you is retired to a rich man, he should follow him.