THAAHAA — Ayat 90
وَلَقَدْ قَالَ لَهُمْ هَارُونُ مِن قَبْلُ يَا قَوْمِ إِنَّمَا فُتِنتُم بِهِ وَإِنَّ رَبَّكُمُ الرَّحْمَنُ فَاتَّبِعُونِي وَأَطِيعُوا أَمْرِي
And Aaron had already told them before [the return of Moses], "O my people, you are only being tested by it, and indeed, your Lord is the Most Merciful, so follow me and obey my order."
Tafsir Ibnu Katsir
وَلَقَدْ قَالَ لَهُمْ هَـرُونُ مِن قَبْلُ يقَوْمِ إِنَّمَا فُتِنتُمْ بِهِ وَإِنَّ رَبَّكُمُ الرَّحْمَـنُ فَاتَّبِعُونِى وَأَطِيعُواْ أَمْرِى - قَالُواْ لَن نَّبْرَحَ عَلَيْهِ عَـكِفِينَ حَتَّى يَرْجِعَ إِلَيْنَا مُوسَى
90. And Harun indeed had said to them beforehand: â€O my people! You are being tried in this, and verily, your Lord is (Allah) the Most Gracious, so follow me and obey my order.'' 91. They said: â€We will not stop worshipping it, until Musa returns to us.'' Allah, the Exalted, informs of Harun's attempt to prohibit them from worshipping the calf and his telling them that this was only a test for them. He told them that their Lord was the Most Beneficent, Who created everything and decreed for everything its just measure. He is the Owner of the Mighty Throne, the One Who does whatever He wants.