The Messenger of Allah ﷺ said, "Whoever grants a debtor in hardship more time, or forgives part of the debt, Allah will shade him under the shade of His Throne on the Day of Resurrection."
حدثنا إسحاق بن سليمان حدثنا داود بن قيس عن زيد بن أسلم عن أبي صالح
أن رسول الله ﷺ قال من أنظر معسرا أو وضع له أظله الله في ظل عرشه يوم القيامة
Its chain of transmission is sahih. Muslim narrated it from Abu Yusr, with the wording, "Whoever grants a debtor in hardship extra time, or writes off the debt for him, Allah will shade him in His shade on the Day when there is no shade except His shade." Suyuti marked it as sahih in Jami Saghir.