Several times in his The Godly Image, Romanus Cessario observes how Greek patristic writers influence Thomas’s understanding of the satisfaction of Christ.
Cessario traces a shift from Thomas’s early Anselmian juridicism to a more personalist understanding of the atonement in his mature work. The difference, he suggests, had to do with the influence of Thomas’s reading of Eastern theology in his composition of Contra errores Graecorum: “Byzantine thought and its characteristic emphasis on divinization and spiritual theology more than compensate for the juridical attitude of satisfaction and morals bequeathed to Aquinas iby the western tradition” (100).
In particular, the instrumental causality of the humanity of Christ was, he argues, “not the peripheral element in the Thomist system which is sometimes represented as being.” Through this concept, Thomas “introduced into western theology the richly suggestive intuition of the Greek Fathers that the very union of God with human nature brought redemption to all that is human. The sacred humanity of Christ, because it is united to the person of the divine Son, is the source from which salvation merited by Christ is physically communicated (that is, by efficient causality) to all who are united in the one mystical person of Christ” (160-1).