Surat Al A`raf: (142-143)

{وَوَاعَدْنَا مُوسَى ثَلاَثِينَ لَيْلَةً وَأَتْمَمْنَاهَا بِعَشْرٍ فَتَمَّ مِيقَاتُ رَبِّهِ أَرْبَعِينَ لَيْلَةً وَقَالَ مُوسَى لأَخِيهِ هَارُونَ اخْلُفْنِي فِي قَوْمِي وَأَصْلِحْ وَلاَ تَتَّبِعْ سَبِيلَ الْمُفْسِدِينَ} [الأعراف: 142]

142- We have promised Moses to speak to him and send down to him a book that contained guidance and codes for the Children of Israel, then We commanded him to fast thirty days in addition to ten more days, thereby the time of the achievement of Allah's Promise became forty nights.

Then Moses said his brother Aaron while he was preparing himself to go to the mountain for speaking with Allah: Be my vicegerent over the Children of Israel during my absence. Be guide to them in obedience by forbearance, kindness, benevolence, and discard differences. Do not follow the way of those who love corruption and disobey Allah, and do not match them in their whims, but be firm on the things that please Allah, and keep to the Straight Path.

{وَلَمَّا جَاء مُوسَى لِمِيقَاتِنَا وَكَلَّمَهُ رَبُّهُ قَالَ رَبِّ أَرِنِي أَنظُرْ إِلَيْكَ قَالَ لَن تَرَانِي وَلَـكِنِ انظُرْ إِلَى الْجَبَلِ فَإِنِ اسْتَقَرَّ مَكَانَهُ فَسَوْفَ تَرَانِي فَلَمَّا تَجَلَّى رَبُّهُ لِلْجَبَلِ جَعَلَهُ دَكّاً وَخَرَّ موسَى صَعِقاً فَلَمَّا أَفَاقَ قَالَ سُبْحَانَكَ تُبْتُ إِلَيْكَ وَأَنَاْ أَوَّلُ الْمُؤْمِنِينَ} [الأعراف : 143] 

143- When Moses came on time and the Lord spoke to him, Moses (peace be upon him) said: O Lord, let me look at you. Allah (Glory be to Him) said: You have no power to see me in this life, but look at the mountain of Tur which is stronger than you. If the mountain keeps firm, you shall see me. When Allah (Glory be to Him) started to appear, the mountain was leveled to the ground and Moses fell in a comma due to the terrible scene he has seen. When he woke up, he said to Allah: How great you are! I repent to you of asking to see you, and truly I am the first believer of the Children of Israel.