Our old history ends with the Cross; our new history begins with the resurrection. “If any man is in Christ, he is a new creature; the old things have passed away; behold they are become new” (2 Cor. 5:17). The Cross terminates the first creation, and out of death there is brought a new creation in Christ, the second Man. If we are “in Adam,” all that is in Adam necessarily devolves upon us; it becomes ours involuntarily, for we have to do nothing to get it. There is no need to make up our minds to lose our temper or to commit some other sin; it comes to us freely and despite ourselves. In a similar way, if we are “in Christ,” all that is in Christ comes to us by free grace, without effort on our part but on the grounds of simple faith.
(from The Normal Christian Life)