Christ was made sin for our sake. We might say that our sins were reckoned to Christ. He, although sinless, identified himself with our sin, suffered their penalty and doom – death. So we have reckoned to us Christ’s righteousness even though in character and deed we remain sinners. It is an unavoidable logical conclusion that men of such faith are justified because Christ’s righteousness is imputed to them.
– George Ladd, A Theology of the New Testament, copyright 1993, page 441
as quoted by John Piper, The Future of Justification: A Response to N.T. Wright, copyright 2007, page 174