Ta-Ha - 20:86
"Moses returned to his people, angry and disappointed, and said, "My people, did not your Lord give you a good promise? Could you not wait? Or did you break your covenant with me in order to incur the wrath of your Lord?"
Our Lord had taken a promise from the Children of Israel through Prophet Moses that they would serve Him alone:
The Cow/2:83
We took a promise from the Children of Israel: You shall serve none but Allah, and you shall do good to parents and relatives and orphans and the poor. You shall speak to people in friendship. You will observe the prayer and pay the zakat. But after that you turned away, except a few of you.