Do the means of the condemnation of the entirety of humanity actually contain the method of our salvation?
I don’t see any other way we could get Christ’s righteousness. And I know many would deny the imputation of Adam’s guilt why affirming the imputation of Christ’s righteousness.
Yes, you are right about this. Romans 5:12-19 is the clearest Scriptural warrant; and here Scripture clearly sets forth that the way our justification works in Christ is exactly the same as our condemnation works in Adam. The implications are huge. Romans 5 sets forth the doctrine that we were condemned in Adam in and through and because of his sin--totally apart from us and any sin we had (as of yet) committed. And in the same way, we are justified in Christ in and through and because of Him, completely apart from any righteousness of ours. As Hodge says: “That doctrine on which the hope of God's people, either implicitly or explicitly, has ever been founded is that the righteousness of Christ as something out of themselves, something distinguished from any act or subjective state of theirs, is the ground of their justification. They know that there is nothing in them on which they dare for a moment rely, as the reason why God should accept and pardon them. It is therefore the essential part of the analogy between Christ and Adam, the very truth which the apostle designs to set forth, that the sin of Adam, as distinguished from any act of ours, and from inherent corruption as derived from him, is the ground of our condemnation. If this be denied, then the other great truth must be denied, and our own subjective righteousness be made the ground of our justification; which is to subvert the gospel. . .The scope of the passage. . .is to illustrate the doctrine of justification on the ground of the righteousness of Christ, by a reference to the condemnation of men for the sin of Adam. The analogy is destroyed, the very point of the comparison fails, if anything in us be assumed as the ground of the infliction of the penal evils of which the apostle is here speaking.” (Romans). And again, in his commentary on Romans: “That we have corrupt natures, and are personally sinners, and therefore liable to other and further inflictions, is indeed true, but nothing to the point. In like manner it is true that we are sanctified by our union with Christ, and thus fitted for heaven; but these ideas are out of place when speaking of justification. It is to illustrate that doctrine, or the idea of imputed righteousness, that this whole passage is devoted; and, therefore, the idea of imputed sin must be contained in the other part of the comparison, unless the whole be a failure.” (Hodge, Romans).
You could draw out the parallels in detail: 1a) If inherent corruption IS the basis of our condemnation in Adam, then inherent righteousness is the basis of our justification in Christ. 1b) But, if inherent corruption is NOT the basis of our condemnation in Adam, then inherent righteousness is NOT the basis of our justification in Christ. 2a) If imputed sin IS the basis of our condemnation in Adam, then imputed righteousness is the basis of our justification in Christ. 2b) But, if imputed sin is NOT the basis of our condemnation in Adam, then imputed righteousness is NOT the basis of our justification in Christ. 3a) But if inherent corruption IS rather the proof/result/outworking/fruit (rather than the basis/grounds) of our condemnation in Adam, then inherent righteousness is the proof/result/outworking/fruit (rather than the basis/grounds) of our justification in Christ. 3b) But if inherent corruption is NOT the proof/result/outworking/fruit (but rather the basis/grounds) of our condemnation in Adam, then inherent righteousness is NOT the proof/result/outworking/fruit (but rather the basis/grounds) of our justification in Christ.
