Briefly defined, this work is penal not chiefly as punishment for God’s offended dignity, but because God’s holy justice requires payment of the debt incurred against his covenant law. It is substitutionary because someone else, namely, the God-Man, Jesus Christ, bears the sanctions (curses) of this law in our place.
This may be true, but I prefer to think of the weight of sin as being due to the nature of the one offended. In that way, the focus is on the majesty and character of God. It's not just that we've offended Him, but that we think so little of violating His Law. So, maybe this statement is actually correct.
