The law of Moses could not save us, because of our sinful nature. But God put into effect a different plan to save us. He sent his own Son in a human body like ours, except that ours are sinful. God destroyed sin’s control over us by giving his Son as a sacrifice for our sins.
—Romans 8:3

The law of Moses says, “do this.” The gospel says, “it is done.” God looked at the law and said, “This might be impossible for you, but nothing is impossible for me.” What was impossible through the law God made possible. It’s impossible for us to save ourselves by doing what we’re told because we can’t do what we’re told.

God put into effect a different plan. He made what’s impossible for us possible when He send His own Son to live the life we should have lived, and die the death we should have died. By doing that, God destroyed sin’s control over us.

In this new plan God does for us and in us what we could not do for ourselves, because of the principle that is at work in us: sin and death. When we own up to this reality we are on the road towards recovery.

Christ became our substitute, conquering sin and ultimately death for us, bringing us to God.

“God sent his Son, who took to himself a nature — a body and all the other components of human nature, with one noticeable exception: he did not take to himself sinful human nature. The incarnate Christ has without original sin. Christ came like us, meaning he looked like us, but not with the sin we are born with. If he had come as sinful flesh, he himself would have been a sinner and could not have saved himself, let alone us. God destroyed sin’s control over us. The cross of Christ was where God poured out his judgment upon human sins. Believers’ sins were imputed to Jesus and God condemned them. That is why there is now no condemnation left for anyone who is in Christ, because the condemnation has already taken place on the cross.
—R.C. Sproul

—Quoted in the Sojourn project, forty: romans eight (to meditate on and memorize Romans 8 over the course of 40 days).