Laylat al-Qadr
A specific date of Laylat al-Qadr is not mentioned in the Quran. This is because Muhammad received the information about the exact date of Laylat al-Qadr from God in a dream. He went to tell the Sahabah about that date. However, he saw two people fighting and forgot what the date was because Allah took the knowledge of Al Qadr from him. With the day of the week, a Muslim date can be fixed exactly.