"The measure of his love for us increases still more when we consider our unworthiness. "Perhaps for a good person one would dare even to die - but God shows his love for us in that while we were still sinners, Christ died for us" (Romans 5:7-8). We deserved divine punishment, not divine sacrifice.
I have heard it said, "God didn't die for frogs. So he was responding to our value as humans." This turns grace on its head. We are worse off than frogs. They have not sinned. They have not rebelled and treated God with the contempt of being inconsequential in their lives. God did not have to die for frogs. They aren't bad enough. We are. Our debt is so great, only a divine sacrifice could pay it."
-- John Piper, The Passion of Jesus Christ - Fifty Reasons Why He Came to Die