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. " (ES)
English reference (ES): Vol. 3, Book 12, Hadith 2203 (ES)
Arabic reference (ES): Book 12, Hadith 2287 (ES)