I ask you again, does God give you the Holy Spirit and work miracles among you because you obey the law? Of course not! It is because you believe the message you heard about Christ.
All Scripture is inspired by God and is useful to teach us what is true and to make us realize what is wrong in our lives. It corrects us when we are wrong and teaches us to do what is right. God uses it to prepare and equip his people to do every good work.