﴿ وَٱخْتَارَ مُوسَىٰ قَوْمَهُۥ سَبْعِينَ رَجُلًۭا لِّمِيقَٰتِنَا ۖ فَلَمَّآ أَخَذَتْهُمُ ٱلرَّجْفَةُ قَالَ رَبِّ لَوْ شِئْتَ أَهْلَكْتَهُم مِّن قَبْلُ وَإِيَّٰىَ ۖ أَتُهْلِكُنَا بِمَا فَعَلَ ٱلسُّفَهَآءُ مِنَّآ ۖ إِنْ هِىَ إِلَّا فِتْنَتُكَ تُضِلُّ بِهَا مَن تَشَآءُ وَتَهْدِى مَن تَشَآءُ ۖ أَنتَ وَلِيُّنَا فَٱغْفِرْ لَنَا وَٱرْحَمْنَا ۖ وَأَنتَ خَيْرُ ٱلْغَٰفِرِينَ ﴾

“And Moses chose out of his people seventy men to come [and pray for forgiveness] at a time set by Us. Then, when violent trembling seized them, he prayed: "O my Sustainer! Hadst Thou so willed, Thou wouldst have destroyed them ere this, and me [with them]. Wilt Thou destroy us for what the weak-minded among us have done? (All] this is but a trial from Thee, whereby Thou allowest to go astray whom Thou willest, and guidest aright whom Thou willest. Thou art near unto us: grant us, then, forgiveness and have mercy on us - for Thou art the best of all forgivers!”

Please check ayah 7:156 for complete tafsir.