The Quran

142

۞ وَواعَدنا موسىٰ ثَلاثينَ لَيلَةً وَأَتمَمناها بِعَشرٍ فَتَمَّ ميقاتُ رَبِّهِ أَربَعينَ لَيلَةً ۚ وَقالَ موسىٰ لِأَخيهِ هارونَ اخلُفني في قَومي وَأَصلِح وَلا تَتَّبِع سَبيلَ المُفسِدينَ

Muhammad Asad

AND [then] We appointed for Moses thirty nights [on Mount Sinai]; and We added to them ten, whereby the term of forty nights set bye, his Sustainer was fulfilled.¹ And Moses said unto his brother Aaron: "Take thou my place among my people; and act righteously, and follow not the path of the spreaders of corruption."

According to several of the Prophet's Companions, and particularly Ibn 'Abbas, the first thirty nights were to be spent by Moses in spiritual preparation, including fasting, whereupon the Law would be revealed to him in the remaining ten (Zamakhshari and Razi); see also Manar IX, 119 ff.). In Arabic usage, a period of time designated as "nights" comprises the days as well.