It was narrated from Jabir bin 'Abdullah that the Messenger of Allah (ﷺ) said:
"May Allah have mercy on a person who is lenient when he sells, lenient when he buys, and lenient when he asks for payment. " (IT)
English reference (IT): Vol. 3, Book 12, Hadith 2203 (IT)
Arabic reference (IT): Book 12, Hadith 2287 (IT)