I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain.
It was too big of a sacrifice to make if there was some other way for salvation to be achieved. If we could do something on our own to be righteous, there was no point in sending Jesus to die an agonizing death on a cross, to suffer as He did. God would never do something frivolously. He does things with purpose, not unnecessarily. So we can conclude that Christ had to die for us and there is no other way. And then if we cling to anything but grace and grace alone for salvation through Christ, we make it as if Christ died in vain.
If we could be righteous, then Christ wouldn’t have had to do anything for us. He wouldn’t have had to die. He could have just been a teacher showing us the way to be righteous. But the whole point is that we could never be righteous. We could never get everything right. We could never fully keep the law or live up to God’s holy standard. It is impossible in our fallen state, full of sin and unrighteousness.
In a way, we would like to be able to do it all ourselves. We like to accomplish things and solve our problems and do things that make us feel good about ourselves. But that only produces pride and self-righteousness that is never pleasing to God. Trying to do it all on our own robs God’s glory and cheapens His sacrifice. Seeking righteousness apart from God is not only fruitless and impossible, but it diminishes the greatness of God and His powerful love for us.
A truth that we don’t always like to readily admit is that we can’t be righteous on our own. But an amazing truth we should be grateful for is that we don’t have to be. Jesus was righteous. Jesus never sinned. Jesus lived a perfect life and followed the law. Jesus gave His life as the spotless Lamb, the atoning sacrifice. And by God’s grace, that is enough for Him. So may it be enough for us, as well.