Bridge's says that his favourite verse in Scripture (which happens to be the same as mine) is 2 Corinthians 5:21: God made him who had no sin to be sin for us, so that in him we might become the righteousness of God. He then explains
That is, God took our sin and imputed (charged) it to Christ, and took His righteousness and imputed (credited) it to us. To put it in a very contemporary form, God treated Christ as we deserved to be treated, so that He might treat us as Christ deserved to be treated.