None of us is righteous; that is not one of us can claim to be justified in the eyes of God. There is an irony here. We cannot, in any wise, gain our own salvation through a single action of of own; but we can lose it through not acting. Does that mean, therefore, that if we assent to believe in Jesus, we are saved? In that case, having thrown salvation by works out of the front door, are we bringing it in by the back one? If we assent to Jesus, we are acting, and by that act we are saved; there is in that a hint of at least the semi-pelagian. We are saved by the Grace of God alone.

But we were bought at a price, a price paid by Jesus on the Cross. The Blood of the Lamb washed us clean. Whatever we suffer, it is nothing compared to what he suffered – and what’s more, Jesus was the only one of us who has been without original sin. 1 John 2:2 states, “He is the atoning sacrifice for our sins.” In the Gospel of John, Jesus is specifically likened to the Passover lamb (see John 19:14,36). The idea is that Christ, being innocent, was a perfect blood sacrifice that took away the sins not just of one person or one congregation, but the whole world.

When Athanasius wrote: “God became human so that humans might become God”, he did  not mean that humans can be another god or equal to God, but rather that we can hope to participate in the divine nature.

The notion of deification (Theosis in Greek) is based on the perspective that when Christ was incarnate in the man Jesus, he did take on just one human nature, but all of human nature. He thus made it possible for the reverse to occur – for humans to participate in the divine nature. “The Son of God, as the one through whom the process of creation was fulfilled, came down from heaven into the world and became fully man, i.e. assumed human nature in its integrity and led it to the fulfillment of its God-given destiny, deification.”

The understanding of salvation as deification is common in eastern Christianity, both in the early patristic fathers and in modern Greek and Russian Orthodoxy. Instances of this doctrine in the early Greek fathers include for example:
We are not made gods from the beginning; first we are mere humans, then we become gods. –St. Irenaeus, Adv Haer III IV:38:4

Let us become the image of the one whole God, bearing nothing earthly in ourselves, so that we may consort with God and become gods, receiving from God our existence as gods –St. Maximus the Confessor On Theology, 7.73

For the Son of God became man, that we might become God. –St. Athanasius, De inc.

He has called men gods that are deified of His Grace, not born of His Substance.–St. Augustine

The Word became flesh and the Son of God became the Son of Man: so that man, by entering into communion with the Word and thus receiving divine sonship, might become a son of God –St. Irenaeus, Adv Haer III

Let us applaud and give thanks that we have become not only Christians but Christ himself. Do you understand, my brothers, the grace that God our head has given us? Be filled with wonder and joy–we have become veritable Christs! –St. Augustine of Hippo

The Only-begotten Son of God, wanting us to be partakers of his divinity, assumed our human nature so that, having become man, he might make men gods. –St. Thomas Aquinas

The highest of all things desired is to become God. –St Basil the Great

This then, is our destiny – unmerited, but an act of purest love. A puzzle as to why God so loved the world that he gave his only begotten Son – but a source of joy that He did.