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

And We made an appointment with Moses for thirty nights and perfected them by [the addition of] ten; so the term of his Lord was completed as forty nights. And Moses said to his brother Aaron, "Take my place among my people, do right [by them], and do not follow the way of the corrupters."