Again, the Commandments of Christ are key to understanding this.
A tad, but the only real difference is a matter of degree. Jesus didn't replace the Law, He set the bar for keeping it MUCH higher. He sets a much higher standard than the Law because He reveals that it's what's in the heart that counts, not just the actions. The Law didn't address that.
So good luck trying to keep what Jesus required of us if you can't keep the Law in the OT, the Ten commandments to start with, to make it easy.
Let us know when you've got those down.