Quran 7:142 Al-A'raf, ayah 142 of 206

۞ وَوَٰعَدْنَا مُوسَىٰ ثَلَـٰثِينَ لَيْلَةً وَأَتْمَمْنَـٰهَا بِعَشْرٍ فَتَمَّ مِيقَـٰتُ رَبِّهِۦٓ أَرْبَعِينَ لَيْلَةً ۚ وَقَالَ مُوسَىٰ لِأَخِيهِ هَـٰرُونَ ٱخْلُفْنِى فِى قَوْمِى وَأَصْلِحْ وَلَا تَتَّبِعْ سَبِيلَ ٱلْمُفْسِدِينَ ۝١٤٢

7:142 And when We did appoint for Moses thirty nights (of solitude), and added to them ten, and he completed the whole time appointed by his Lord of forty nights; and Moses said unto his brother, Aaron: Take my place among the people. Do right, and follow not the way of mischief-makers.