Surah Al-Baqarah 2:51

وَإِذْ وَٰعَدْنَا مُوسَىٰٓ أَرْبَعِينَ لَيْلَةً ثُمَّ ٱتَّخَذْتُمُ ٱلْعِجْلَ مِنۢ بَعْدِهِۦ وَأَنتُمْ ظَـٰلِمُونَ

And [recall] when We made an appointment with Moses for forty nights. Then you took [for worship] the calf after him [i.e., his departure], while you were wrongdoers.

Translation: Saheeh International

Tafsir

And when We appointed for wā‘adnā or wa‘adnā Moses forty nights at the end of which We shall give him the Torah for you to implement then you took to yourselves the calf the one which the Samaritan fashioned for you as a god after him that is after he departed for Our appointment and you were evildoers for taking it …

Excerpt from Tafsir al-Jalalayn, commentary on 2:51, via Quran.com. The reader has the full commentary and 9 more tafsirs.