40 Hadith Qudsi #36

On the authority of Anas (may Allah be pleased with him) from the Prophet (ﷺ), who said: The believers will gather together on the Day of Resurrection and will say: Should we not ask . So I shall admit them into Paradise. Then I shall return for a third time, then a fourth, and I shall say: There remains in Hell-fire only those whom the Qur'an has confined and who must be there for eternity. There shall come out of Hell-fire he who has said: There is no god but Allah and who has in his heart goodness weighing a barley-corn; then there shall come out of Hell-fire he who has said: There is no god but Allah and who has in his heart goodness weighing a grain of wheat; then there shall come out of Hell-fire he who has said: There is no god but Allah and who has in his heart goodness weighing an atom. It was related by al-Bukhari (also by Muslim, at-Tirmidhi, and Ibn Majah).