Donald Fairbairn has written an excellent essay on justification in the theology of Cyril of Alexandria over at the most recent offering of Participatio which is the Thomas F. Torrance Theological Fellowship’s theological journal (I serve as an assistant editor). Here is the abstract to his essay (which starts on pg. 123 of vol. 4):

Abstract: T. F. Torrance once commented that no one in the history of theology has ever expounded the evangelical doctrine of justification by grace better than St. Cyril of Alexandria. Torrance never substantiated this surprising claim, and this article attempts to do so by exploring Cyril’s concept of justification. It surveys the vocabulary Cyril uses for justification or righteousness and analyzes four key exegetical passages in depth, concluding from this analysis that Cyril uses active and passive forms to show that righteousness has its source in God/Christ/grace, comes to the Christian from the outside, and is received by faith. The article further analyzes the relation between justification and sanctification in Cyril’s thought, arguing that Cyril uses both of these terms to refer to a righteousness given to the Christian from the outside, rather than to an internally produced righteousness. The article concludes by noting points of contact with and differences between Cyril’s understanding and both modern Protestantism and modern Eastern Orthodoxy. It suggests that Cyril’s concept of the Christian’s personal participation in the Son’s relationship to the Father, from which both justification and sanctification flow, may be a helpful subject for ecumenical dialogue between Protestants and the Orthodox. [click here for Vol 4. Thomas Torrance and Orthodoxy]

This doctrine from Cyril would fit very nicely with John Calvin’s ‘double grace’ theology, which you can read about in J. Todd Billings’ book: Calvin, Participation, and the Gift: The Activity of Believers in Union With Christ.  I would encourage you to check out Fairbairn’s essay (and the rest of the essays that make up that volume); his essay, in my view, is one of the best in that volume.