It was narrated from Buraidah Al-Aslami that the Prophet (ﷺ) said:
"Whoever gives respite to one in difficulty, he will have (the reward of) an act of charity for each day. Whoever gives him respite after payment becomes due, will have (the reward of) an act of charity equal to (the amount of the loan) for each day."
English reference: Vol. 3, Book 15, Hadith 2418
Arabic reference: Book 15, Hadith 2511