Sunan an Nasai
4688
Sahih+2

It was narrated that Abu Hurairah said:"The Messenger of Allah said: 'If one of you is referred to a rich man (to help repay a debt), he should accept that referral, and (wrongdoing) is when a rich man takes a long time to repay a debt

SahihAbu Ghuddah
SahihAl-Albani