Al A'raf, 142 Ayah
7:142
۞ وَوَٰعَدۡنَا مُوسَىٰ ثَلَٰثِينَ لَيۡلَةٗ وَأَتۡمَمۡنَٰهَا بِعَشۡرٖ فَتَمَّ مِيقَٰتُ رَبِّهِۦٓ أَرۡبَعِينَ لَيۡلَةٗۚ وَقَالَ مُوسَىٰ لِأَخِيهِ هَٰرُونَ ٱخۡلُفۡنِي فِي قَوۡمِي وَأَصۡلِحۡ وَلَا تَتَّبِعۡ سَبِيلَ ٱلۡمُفۡسِدِينَ ١٤٢
Wa Wā`adnā Mūsá Thalāthīna Laylatan Wa 'Atmamnāhā Bi`ashrin Fatamma Mīqātu Rabbihi 'Arba`īna Laylatan ۚ Wa Qāla Mūsá Li'khīhi Hārūna Akhlufnī Fī Qawmī Wa 'Aşliĥ Wa Lā Tattabi` Sabīla Al-Mufsidīna
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."