Galatians 2:21 I do not frustrate the grace of God: for if righteousness is attainable by the law, then Christ hath died in vain. (WBS)
Hebrews 7:11 Now if the crowning blessing was attainable by means of the Levitical priesthood--for as resting on this foundation the people received the Law, to which they are still subject-- what further need was there for a Priest of a different kind to be raised up belonging to the order of Melchizedek instead of being said to belong to the order of Aaron? (WEY RSV)