The smashing of the Old law was this:
Exodus 32:16-20
16 The tablets were the work of God, and the writing was the writing of God, engraved on the tablets. 17When Joshua heard the noise of the people as they shouted, he said to Moses, "There is a noise of war in the camp." 18But he said, "It is not the sound of shouting for victory, or the sound of the cry of defeat, but the sound of singing that I hear." 19And as soon as he came near the camp and saw the calf and the dancing, Moses anger burned hot, and he threw the tablets out of his hands and broke them at the foot of the mountain. 20He took the calf that they had made and burned it with fire and ground it to powder and scattered it on the water and made the people of Israel drink it.
Moses didn't smash the tablet because the people weren't ready, he shamed it accidentally because he was angry at the people for molding a golden calf and celebrating it. Then Moses goes back up to God and intercedes on the Israelites behalf so that God does not destroy them. In chapter 34 we see Moses cutting a new tablet and God wrote on it...and God gives it to the same people. We are not told that there were different 10 commandments on the second tablet. In the 10 commandments, the first 4 verses, deal with the love that Israelites should have for God and the the last 6 verses deal with the way they should love and treat each other. And Christ in the New Testament is telling us that we should love God and love each other, for Loving God is the greatest command.
God considers you to have sin when you break His commandments not simply just the "love thy neighbor" command. We are told that love thy neighbor is the fulfillment of the law.
Answer this question: Did this person sin because he did not love his neighbor or because he broke a law that God told him not to?
Numbers 15:32-36
While the people of Israel were in the wilderness, they found a man gathering sticks on the Sabbath day. And those who found him gathering sticks brought him to Moses and Aaron and to all the congregation. They put him in custody, because it had not been made clear what should be done to him. And the LORD said to Moses, "The man shall be put to death; and the congregation shall stone him with stones outside the camp." And all the congregation brought him outside the camp and toned him to death with stones, as the LORD commanded Moses."
We are not told that he didn't love his neighbor, nor can I assume he didn't love his neighbor based on the law he broke. All I can assume is that he broke a commandment of God and his punishment was death.
New Testament does have commands for us. The commandments that Christ taught some of them does go back to the old law, and some of them are new, but the Old law was a tutor for the new (Galatians 3:23-25). And there were some things that Christ didn't have to explain because the Jews understood it, like sexual immorality. They would have understood what that meant. And that's why I said we should go back and read what God considers sexually immoral in the Old law to see what they are.
I am not quite sure why this came about, because I did say that "Love God with all your heart, soul, and mind" is the greatest command. For if you love God and love your neighbor following His laws, will be much easier.
And to be honest with you, I don't understand how to even interpret "NOT the other way around." I was unaware that I said that you must follow the Old law in order to love God and love your neighbor. I said that we should know what God considers sin because it is He who determines what sin is.