It is narrated that Moses, peace be upon him, promised the Children of Israel while he was in Egypt that if Allah destroyed their enemy, He would bring them a book from Allah in which there is clarification of what they should do and what they should avoid. When Pharaoh was destroyed, Moses asked his Lord for the book. Allah commanded him to fast for thirty days, which is the month of Dhul-Qi'dah. When he completed the thirty days, he noticed a bad breath in his mouth due to the fasting, so he used a miswak. The angels said: 'We used to smell the scent of musk from your mouth, but you spoiled it with the miswak.' It was said: Allah, glorified and exalted is He, revealed to him: 'Did you not know that the bad breath of the fasting person is more pleasant to Me than the scent of musk?' Therefore, Allah commanded him to add ten more days from Dhul-Hijjah for that reason. It was said that Allah commanded him to fast for thirty days and to do good deeds during them that would bring him closer to Allah, then the Torah was revealed to him in the last ten days, and he spoke with Allah in it. The mention of the forty days is summarized in Surah Al-Baqarah, and it is detailed here. The appointed time of his Lord is what He appointed for him from the time and specified for him. And 'forty nights' is in the accusative case, meaning he reached this number. And 'Aaron' is an apposition to his brother. It is also recited with a vowel on the call: 'Be my successor among my people, and be a reformer.' Or reform what needs to be reformed among the Children of Israel, and whoever among them calls you to corruption, do not follow him and do not obey him.