Okay, I know you have been waiting with bated breadth to hear an explanation of why Tweety Bird’s statement is so fascinating. In short, she (I think it is a “she”) articulates an understanding of justification that is neither classically Protestant (according to the Magisterial Reformers at least) or exactly Catholic (although it is arguably compatible with Roman Catholic teaching). It is, however, exactly the way John Henry Newman (1801-1890) would summarize the reason for one’s justification (i.e. why one is “covered in the blood of Jesus”). And since I an completing my Ph.D. thesis on Newman’s doctrine of justification in the context of Catholic and Protestant theology, thank you for indulging me on this rather bizarre post. Here is how I would summarize it:
According to Alister McGrath, the leading characteristics of the Protestant outlook on justification are threefold: First, justification involves a “forensic declaration that the Christian is righteous,” that is, a change in one’s legal status before God (as opposed to a process of internal renewal by which one is made righteous). Second, there is a “deliberate and systematic distinction” between the forensic activity of justification and the internal process of sanctification or regeneration. Third, “justifying righteousness or the formal cause of justification” is alien, external, and imputed. Therefore, according to an evangelical Protestant reading of Scripture, the ground or fundamental reason why someone is “covered by the blood of Christ” is the imputed righteousness of Christ (and not, as Tweety Bird suggests, divine indwelling… “because [Jesus] lives in me”).
On the other side of the ecclesial divide, the Roman Catholic Church responded to Protestant arguments by convening the Council of Trent (1545-1563) where it defined its doctrine in its Decree on Justification (1547). Rejecting the Protestant view of “faith alone” grounded in the forensic imputation of Christ’s righteousness, the Roman Church chose to emphasize the “process” of justification whereby the gift of righteousness is internally “infused” through her Sacraments, a process expressed in moral virtues and good works as the necessary condition for man’s final absolution. As for the contemporary significance of Trent’s teaching, Avery Cardinal Dulles, S.J., explains that the “theology of justification in Roman Catholic teaching has undergone no dramatic changes since the Council of Trent.”
Distinct from both of these approaches is the teaching of John Henry Newman in his famous Lectures on the Doctrine of Justification (1838; republished as a Catholic in 1874) According to Newman, justification comes to one’s soul by the Holy Spirit, who properly imputes the righteousness of Christ by means of divine indwelling. Newman asserts, “This is really and truly our justification, not faith, not holiness, not (much less) a mere imputation; but through God’s mercy, the very Presence of Christ. Thus, the cause of justification is, in Newman’s terms, “adherent” righteousness, “depending wholly and absolutely on the Divine Indwelling.” Simply stated, “Justifying righteousness consists in the coming and presence of the Holy Ghost within us.”
To what extent Tweety read Newman we can’t say. But we can be thankful for her thought-provoking statement, which leads us to reflect on the reason why we are covered by the blood of Jesus and how this relates to divine indwelling. We Reformed Protestants do not locate the formal “cause” of justification in divine indwelling, but we ought to be able to explain on some level how forensic justification and indwelling relate.
 Alister McGrath, “Forerunners of the Reformation? A Critical Examination of the Evidence for Precursors of the Reformation Doctrines of Justification,” Harvard Theological Review 75 (1982):219-242; (idem, Iustitia Dei, 212-213). Berndt Hamm’s conclusions support this taxonomy vis-à-vis the formal cause (192), imputation (194), and distinction of justification from sanctification (196). The Reformation of Faith in the Context of Late Medieval Theology and Piety: Essays by Berndt Hamm (ed. Robert J. Bast. Leiden: Brill, 2004). For the historical antecedents to these characteristics, see A.N.S. Lane, Justification by Faith in Catholic-Protestant Dialogue: An Evangelical Assessment (London: T&T Clark, 2002), 138-140.
 Chapter seven of the Decree on Justification explains “What the justification of the sinner is and what are its causes.” Decrees of the Ecumenical Councils, ed. Norman P. Tanner, vol. 2 (London: Sheed & Ward, 1990), 673.
 Avery Cardinal Dulles, S.J. “Justification in Contemporary Theology,” in Justification by Faith: Lutherans and Catholics in Dialogue VII, ed. H. George Anderson et al. (Minneapolis: Augsburg, 1985), 256. According to A. N. S. Lane, even if the Joint Declaration on the Doctrine of Justification (1999) is taken into account, the positive exposition of the Tridentine decree remains incompatible with a Protestant understanding, even though the gap is narrower than it was previously. Anthony N. S. Lane, Justification by FaitH, 223.
 Newman, Lectures on the Doctrine of Justification, 167, .
 Ibid., 218 .
 Ibid., 155 .