Every single law, every single command ever utter by God to us was for our instruction, benefit and well-being. The fact that we rebel against God's laws and commands shows to us that while God has our best intention at heart, WE don't. Otherwise we would simply follow God's commands. When God calls us "evil", "wicked", or "perverse", He is merely stating what should be obvious to all of us; that we are in constant rebellion to everything that would lead to our happiness. It is God's great grace through our Lord Jesus that helps us somewhat of our mess.
To believe one can keep parts of the law and ignore other parts fails to show an understanding of the real intent of the Law. There was, after all, a real purpose of God for having people slice the throats of animals and letting the blood flow around the altar. Without the high cost of the sacrifice and the stench and mess it made, one could not truly understand how much just ONE sin appears to God.
The law was never a means of holiness. Nor was it God's way of putting in front of us an impossible task. It was simply to show that while God wants the very best for us, we do not. And anything that God doesn't want is sin, rebellion and evil (I know that's redundant but it's to make a point).
And the people chosen for instruction was Israel. That has not changed. That covenant was to bring them to their knees,as Christ was to his under the weight of their sins, but only as prelude to raising them up, he the first.