In this essay, I argue that the Incarnation of the Son of God, understood in a traditionally orthodox way, is incompatible with an atemporalist concept of God. First, I explain what I mean by atemporalism, namely the idea that God exists outside time. I also show the main corollaries of that doctrine, most notably that all of God’s life occurs eternally simultaneously. Second, based on New Testament teaching and widely accepted creeds, I spell out philosophically what I mean by the Incarnation. In short, I take it to be the doctrine that the Second Person of the Trinity at some point in time took on a human body as part of a fully human nature. I then proceed to my central argument, which derives a contradiction from the definitions of the Incarnation and of atemporalism, respectively. In the last section, I shall treat some possible objections to my argument and show that they do not solve the problem satisfactorily.