Mishkat al-Masabih 11 Business Transactions كتاب البيوع 144

وَعَنْهُ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ: «مَطْلُ الْغَنِيِّ ظُلْمٌ فَإِذَا أُتْبِعَ أحدكُم على مَلِيء فَليتبعْ»

He reported God’s Messenger as saying, “Delay in payment by a rich man is injustice, but when one of you is referred for payment to a wealthy* man he should accept the reference.” (Bukhari and Muslim.) * Mali’ . This word is used of a wealthy man, and also of one who cannot be called wealthy but who is careful to pay his debts.