How Christ Magnified the Law

Why do people sin? Are we a 'tabula rasa'(blank slate)with the circumstances of life causing us to sin or is it the sin nature we are born with? How is it that the writer of Psalm 119 by the Holy Spirit is able to say he kept the law completely? How is Christ the believer's Righteousness? How was Righteousness earned? Was it by Christ keeping the law only? Can God lower His standard for sinners? How was God's standard met by Christ the Substitute? Did Christ ever waiver in His keeping of the law? Why did Christ pray 'Thy will be done'? What did He mean by the horror He endured?