Bingo.
The Bible says the law was given as a schoolmaster to bring us to Christ. "The just shall live by faith" not the law.
The law is the Tree of the Knowledge of Good and Evil. Grace is the Tree of Life. Israel in its pride said, "We can do all that you tell us." Then God say, OK, here's the law. Next thing you know, they're worshiping the golden calf and stuff. Why? Because the strength of sin is the law (1 Cor 15:56).
We were created for fellowship with God. We were never created to try to perform apart from him or establish our own righteousness by our good works. The law brings out the sin that lies dormant in our flesh. That is why it is meant to teach us that we can't do it and we need Christ who has already done it.
The Christian life is not "DO", but "DONE": "It is finished."
It just doesn’t make sense. The Golden calf was before the Hebrews knew that there was a law. I realize that we mere mortals cannot discern G-d’s purpose, but you should also keep that in mind. Your claim is that G-d changed his mind in 1400 years, or was committing fraud on HIS people. I don’t believe that either is true.