But the sacrificial Lamb who died for our sins in the New Testament was provided by God Himself. An all sufficient Lamb . Now, another word for complete is Perfect, and another word for perfect is Unblemished, or Flawless. God did not have to improve on the Lamb that He sent. God is not like man.
Man needs new and improved products.
Man can devise things like automobiles. Modern transportation enables man to travel in ways and speeds that were formerly impossible. Yet man sees need for improvement in these things. The auto of 1917 is no longer sufficient for today. Possibly all things man has created, or produced in years past are no longer sufficient for man today.