Now it is evident that no person is justified (declared righteous and brought into right standing with God) through the Law, for the Scripture says, The man in right standing with God [the just, the righteous] shall live by and out of faith and he who through and by faith is declared righteous and in right standing with God shall live. [Hab. 2:4.] (Galatians 3:11 AMP)
In order to please our God, in order to be near Him, it's not necessary for us to obey all of the Law. That would include the Ten Commandments and all of the laws Moses took down from God about the rituals and principles of right living. They are numerous, would be impossible for us to obey and so our God would be displeased with us. Because of His holiness He couldn't live in our needy hearts.
So beginning with Abraham God taught us to live by faith in Him. Abraham looked forward in time to the day the Lord would sacrifice His Son, Our Savior. That's faith. We look back in time to the same. That's faith.
But living by faith is something else also. It's not rules to obey by rote but by tender heart. Loving Him, worshiping Him, reading His word, praying, all for the purpose of being near Him. His love for us is so strong and yet gentle, returning the love is tough to resist when you're worshiping Him, reading His word, and praying.