We seem to think the message is that we can’t do it: Be good; be righteous; be perfect--in essence, be saved. But Jesus’ message is that we can.
To say we, ourselves, can’t attain justification or righteousness is to simply say the same thing as the law of Moses.
It is to make Christ merely a replacement of the law of Moses. But Christ is not a replacement of the law of Moses, He is its fulfillment—its perfection. He is that which enables us to attain what he attained in Himself for us through His Father. We can only have a relationship with the law as a with a thing; as with a judge; a thing outside of us that is not us, that judges us and judges for us. Whereas we can have a relationship with the living God as with ourselves—closer to our being than ourselves—as a Father. A relationship with the giver of being itself. A thing infinitely intimate as humanly possible. A thing both infinitely close as it is infinitely far. A Christ within us that is like us and judges from within us and through us and to us. So that we ourselves may judge correctly—and the judgement He judges from within us is only and ever the living and the dead.