The inheritance existed because of a promise made to Abraham. The Law was needed because of Israel's failure to follow God's purposes and will. The Law had its origin in God, and both angels and Moses were mediators. It was to be in force until the SEED could come and make God's promise a reality. It did not oppose the promise, but it had a specific limitation.
Scripture confirms that all people are the prisoners of sin.
Only through Christ can people be released from that prison. Faith in Christ makes that promise reality. Permission is granted to freely copy and distribute with text unchanged, including author's name.