Rahner believes that the saviour described by his "transcendental Christology" is not diverse from the one presented by the classic Christological formulations of Chalcedon, which used a concept of "hypostatic union" to claim Jesus as the Christ. Accordingly, he then proceeds to articulate the meaning of the "hypostatic union". The issue is how to understand the meaning of "human being": Rahner understands the phrase “became man” as assuming an individual human "nature" as God's own, and emphasises "the self-emptying of God, his becoming, the kenosis and genesis of God himself". God "assumes by creating" and also "creates by assuming", that is, he creates by emptying himself, and therefore, of course, he himself is in the emptying. He creates the human reality by the very fact that he assumes it as his own. God's creating-by-emptying act belongs to God's power and freedom as the absolute One and to God's self-giving love expressed in scripture. Therefore, it is legitimate for Rahner to assert that God "who is not subject to change in himself can "himself" be subject to change in "something" else". This is what the doctrine of the Incarnation teaches us: "in and in spite of his immutability he can truly become something: he himself, he in time".