Hadith #20 (The Forty Hadith Qudsi)
Narrator(s): Abu Hurayrah
Grade: Sahih

On the authority of Abu Hurayrah (may Allah be pleased with him), who said that the Messenger of Allah (ﷺ) said: The gates of Paradise will be opened on Mondays and on Thursdays, and every servant [of Allah] who associates nothing with Allah will be forgiven, except for the man who has a grudge against his brother. [About them] it will be said: Delay these two until they are reconciled; delay these two until they are reconciled.

Source: https://parallelquran.com/hadith/forty-qudsi-20/