Abstract: This dissertation is a study of Martin Luther’s concept of communicatio idiomatum and its soteriological implications for Shankara’s mahavakya: Aham Brahmasmi. In this study I elucidate how Luther developed the concept of communicatio idiomatum to explain the mysterious unity between the divine and the human natures in the one person of Christ. In Luther’s case, this unity affirms our actual human life in and through suffering, as the Godhead takes this actual human experience into the divine life. Communicatio idiomatum in Luther’s Christology becomes soteriology. Shankara, in contrast, teaches that the ultimate goal for humanity is to be liberated from ignorance (avidya) in the actual world and be united with Brahman. I argue that human actuality, personal history, or suffering is not addressed when it is denied as maya. Actuality can never be experienced as illusion by the suffering masses, poorest of the poor, dalits, women, and wounded in the world. When Luther’s understanding of communicatio idiomatum is brought to bear on the dalit experience, I contend that the actuality of suffering humanity, the actuality of the cross, and actuality for struggle for justice, all become real to the Godhead. My research methodology is both historical-genetic—explicating Luther and Shankara in their respective contexts—and doctrinally systematic—drawing out implications for fundamental ontology. I show in the study of three activist/theologians; Gurram, Sobrino, and Soelle, that it is in the suffering reality of the dalits, the poor, the women, the victims and the wounded, that God is present and communicates the divine nature for redemption. God takes the suffering reality of the oppressed and restores all that has been taken away from the oppressed and in addition gives the oppressed majesty, righteousness and glory. Thus, the soteriological communicatio idiomatum between the oppressed and God by grace through Jesus Christ, becomes a reality in faith. I conclude that any soteriology or system that does not have such perspective loses its soteriological significance and becomes an oppressive structure. The suffering servant in whom both the human and divine natures come together in unity and communication leads us towards the knowledge and experience of the ultimate Truth.