It is recommended to fast on Mondays and Thursdays; as Aisha (may Allah be pleased with her) said: "The Prophet (peace be upon him) used to seek to fast on Mondays and Thursdays," in Jami' at-Tirmidhi 3: 121, and he graded it as good, and in Musnad Ahmad 6: 80. And from Usama ibn Zaid (may Allah be pleased with him), he said: "I said: O Messenger of Allah, you fast until you hardly break your fast, and you break your fast until you hardly fast except on two days, if they enter into your fasting, otherwise you fast them. He said: Which two days? I said: Monday and Thursday. He said: Those are two days when deeds are presented to the Lord of the Worlds, and I like my deeds to be presented while I am fasting," in Sunan an-Nasa'i 2: 121, Al-Mujtaba 4: 201, Al-Ahadith Al-Mukhtarah 4: 142, Musannaf Ibn Abi Shaybah 2: 301, Musannaf Abdul Razzaq 4: 314, and Musnad Al-Bazzar 7: 69. And from Abu Qatadah (may Allah be pleased with him): "The Prophet (peace be upon him) was asked about fasting on Monday, he said: That is the day I was born on and the day I was sent or the day it was revealed to me," in Sahih Muslim 2: 819, and Sahih Ibn Hibban 8: 403. 17. What are the white nights, and what is the ruling on fasting them? They are the thirteenth, fourteenth, and fifteenth of every lunar month, and they are called white because of the brightness of their nights due to the moon; it rises from the beginning to the end of them. It is recommended to fast them unless one thinks it is obligatory, as in Al-Bahr Al-Ra'iq 2: 287, Hashiyat Al-Tahbiyyin 1: 332, and Bada'i' Al-Sana'i' 2: 79; as Abu Huraira (may Allah be pleased with him) said: "My beloved (peace be upon him) advised me with three things: to fast three days of every month, to pray two rak'ahs of Duha, and to pray Witr before I sleep," in Sahih Al-Bukhari 2: 699. And from Abu Qatadah (may Allah be pleased with him), the Prophet (peace be upon him) said: "Fasting three days of every month and Ramadan to Ramadan is the fasting of the whole year," in Sahih Muslim 2: 819. And from Abu Dharr (may Allah be pleased with him), he said: "The Messenger of Allah (peace be upon him) commanded us to fast the thirteenth, fourteenth, and fifteenth," in Sahih Ibn Hibban 8: 414. And from Abu Al-Munhal (may Allah be pleased with him): "The Prophet (peace be upon him) commanded them to fast the three white days, and he said: They are the fasting of the month," in Sunan an-Nasa'i 2: 182, Al-Mujtaba 4: 224.