Torah was to show them to Christ. It was to show them that they could never follow all those rules. For them to realize they couldn't follow all the rules and call onto God. God knew they could never set them selves free by their actions. So Jesus had to come and then we could follow him and be set free by his blood. I hope this helps you. God bless!
Great answer.
The law was given because of sin, until the coming of the Messiah according to the Apostle Paul. Now that faith in Jesus has come, we are no longer under that law. In Hebrews it speaks of the New Covenant.
God says he will write His laws on our hearts and put them on our minds, by the Holy Spirit. No longer will a man need to teach His neighbour concerning them. If something is written on our hearts we naturally want to obey, but can only do so through the Spirit. You are right no-one could really obey those laws. If they could Jesus needn't have died.
Sin used the good laws of God to condemn the Apostle Paul.
Does this mean we have all 613 laws written in our hearts and minds? No
And this is His command. To believe in the name of His Son Jesus Christ, and to love one another as He commanded us.. 1John3:23
As Paul says. Love fulfills the Law.
Anything else is legalism. And love is the first casualty of legalism.