7:142
۞ وَوَٰعَدْنَا مُوسَىٰ ثَلَـٰثِينَ لَيْلَةً وَأَتْمَمْنَـٰهَا بِعَشْرٍ فَتَمَّ مِيقَـٰتُ رَبِّهِۦٓ أَرْبَعِينَ لَيْلَةً ۚ وَقَالَ مُوسَىٰ لِأَخِيهِ هَـٰرُونَ ٱخْلُفْنِى فِى قَوْمِى وَأَصْلِحْ وَلَا تَتَّبِعْ سَبِيلَ ٱلْمُفْسِدِينَ
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."
Context in Surah Al-A'raf
Nearby ayahs help place verse 7:142 in sequence and meaning.
قَالَ أَغَيْرَ ٱللَّهِ أَبْغِيكُمْ إِلَـٰهًا وَهُوَ فَضَّلَكُمْ عَلَى ٱلْعَـٰلَمِينَ
He said, "Is it other than Allah I should desire for you as a god while He has preferred you over the worlds?"
وَإِذْ أَنجَيْنَـٰكُم مِّنْ ءَالِ فِرْعَوْنَ يَسُومُونَكُمْ سُوٓءَ ٱلْعَذَابِ ۖ يُقَتِّلُونَ أَبْنَآءَكُمْ وَيَسْتَحْيُونَ نِسَآءَكُمْ ۚ وَفِى ذَٰلِكُم بَلَآءٌ مِّن رَّبِّكُمْ عَظِيمٌ
And [recall, O Children of Israel], when We saved you from the people of Pharaoh, [who were] afflicting you with the worst torment - killing your sons and keeping your women alive. And in that was a great trial from your Lord.
وَلَمَّا جَآءَ مُوسَىٰ لِمِيقَـٰتِنَا وَكَلَّمَهُۥ رَبُّهُۥ قَالَ رَبِّ أَرِنِىٓ أَنظُرْ إِلَيْكَ ۚ قَالَ لَن تَرَىٰنِى وَلَـٰكِنِ ٱنظُرْ إِلَى ٱلْجَبَلِ فَإِنِ ٱسْتَقَرَّ مَكَانَهُۥ فَسَوْفَ تَرَىٰنِى ۚ فَلَمَّا تَجَلَّىٰ رَبُّهُۥ لِلْجَبَلِ جَعَلَهُۥ دَكًّا وَخَرَّ مُوسَىٰ صَعِقًا ۚ فَلَمَّآ أَفَاقَ قَالَ سُبْحَـٰنَكَ تُبْتُ إِلَيْكَ وَأَنَا۠ أَوَّلُ ٱلْمُؤْمِنِينَ
And when Moses arrived at Our appointed time and his Lord spoke to him, he said, "My Lord, show me [Yourself] that I may look at You." [Allah] said, "You will not see Me, but look at the mountain; if it should remain in place, then you will see Me." But when his Lord appeared to the mountain, He rendered it level, and Moses fell unconscious. And when he awoke, he said, "Exalted are You! I have repented to You, and I am the first of the believers."
قَالَ يَـٰمُوسَىٰٓ إِنِّى ٱصْطَفَيْتُكَ عَلَى ٱلنَّاسِ بِرِسَـٰلَـٰتِى وَبِكَلَـٰمِى فَخُذْ مَآ ءَاتَيْتُكَ وَكُن مِّنَ ٱلشَّـٰكِرِينَ
[Allah] said, "O Moses, I have chosen you over the people with My messages and My words [to you]. So take what I have given you and be among the grateful."